Questions? We keep it short.

Yes, and it's free. When you order, you say you want to keep your current number and give the details of your current operator. We handle the transfer.

• Enter your customer number and the SIM card number of your old operator exactly. A mistake there is the most common reason a transfer is refused.

• Your old SIM card keeps working until the transfer is done. You get a text as soon as your number is active with UNDO.

• Your old subscription ends automatically. You don't need to cancel it yourself.

You can follow the status in the app or in My UNDO, under YOUR TARIFF. As long as the box around your number is grey, the transfer is still running. Once it turns green, your number is active.

Yes, with a SIM SWAP. In the app or in My UNDO, go to MANAGE under YOUR TARIFF and choose SIM SWAP. Choose eSIM and follow the steps. You get a new QR code by email, which you install on your new phone.

Once your eSIM is installed, it's moved over on the network. That can take up to 2 hours. You get a text as soon as it's active.

Don't delete your eSIM from your old device before you request the SIM SWAP. That way you stay reachable until the new eSIM works.

Yes, in your smartphone settings. We advise against it: without a PIN code, anyone can use your SIM card if you lose your phone.

No, not yet. That way you stay reachable until your new eSIM works. The right order:

1. Request a SIM SWAP in the app or in My UNDO.

2. You get a new QR code by email.

3. Scan it on your new device.

4. Once your new eSIM is active, the old one stops automatically. Then you can safely delete it.

Already deleted it? No problem, but you won't be reachable until the SIM SWAP is done.

Both. When you order, you choose an eSIM or a classic SIM card. If you choose an eSIM, you enter the brand and model of your smartphone and we check right away whether your device supports eSIM.

An eSIM costs nothing extra, you get it by email and it's usually active within the hour. A classic SIM card is a multi-size SIM card: you push out the right size yourself (standard, micro or nano). Shipping it costs €5.

Received your SIM card? In the app or in My UNDO, click ACTIVATE, enter the 13-digit SIM card number and confirm.

A new number or a SIM SWAP is usually active within the hour. If you're keeping your number, the waiting time depends on your current operator. You get a text as soon as your number is active, and the box around your number in the app turns green.

After your order you get an email with a QR code and a PIN code. Is the eSIM for someone else? Just forward the email.

1. Scan the QR code with your device's camera.

2. Follow the steps and unlock your eSIM with the PIN code from the email.

3. You get a text as soon as your eSIM is active.

Important: don't delete the installed eSIM from your device. You can only install a QR code once.

Can't scan it? You can also add the eSIM manually:

• iPhone: Settings > Mobile Service > Add eSIM > Use QR Code.

• Android: Settings > Connections > SIM manager > Add eSIM > Scan QR code from service provider, and confirm.

You can do it online or in the app:

1. Choose your subscription and log in with itsme to create your account.

2. Choose an eSIM or a classic SIM card, and whether you're keeping your number.

3. Confirm your order. You get a confirmation by email.

If you choose an eSIM, you get a second email with your QR code. An eSIM is usually active within the hour. If you're keeping your number, the waiting time depends on your current operator.

When you order, after choosing your SIM card, you get a screen to confirm your delivery address. Click Edit there and enter the correct address.

Your default PIN code is on the plastic card of your SIM card or in the email with your QR code. Best change it to a code only you know.

On your phone, type **04*old PIN*new PIN*new PIN# and press the call button. For example, for 1375: **04*0000*1375*1375#.

Don't choose consecutive digits (1234) or four identical digits (2222).

In the app or in My UNDO, click MORE and SETTINGS, and choose the language of your SIM card. The chosen language turns green once it's changed. Your voicemail switches to that language too.

In the app, go to your number under YOUR TARIFF, swipe left and click ORDER. In My UNDO, click ORDER to the right of your number.

You can only order an extra SIM card if all your invoices are paid.

Request a SIM SWAP. In the app or in My UNDO, go to MANAGE under YOUR TARIFF and choose SIM SWAP. Choose a classic SIM card and follow the steps.

Once you've received the SIM card, activate it in the app and put it in your smartphone. You get a text as soon as it's active.

Request a SIM SWAP. In the app or in My UNDO, go to MANAGE under YOUR TARIFF and choose SIM SWAP. Choose eSIM and follow the steps. You get a QR code by email.

Once your eSIM is installed, your number is moved over on the network. That can take up to 2 hours. You get a text as soon as your eSIM is active.

With an eSIM you're usually active within the hour. A classic SIM card is shipped within 1 working day and usually delivered by courier within 2 working days.

If you keep your number, the transfer usually takes less than 24 hours. That depends on your current operator, who has to release your number. Until then, your old SIM card keeps working.

Up to 7 as a private customer and up to 100 as a company. Need more for your company? Get in touch via the Business page.

Try this first:

• Check that you're entering the full 13-digit SIM card number correctly. It's on the back of the plastic holder.

• Did you request a number transfer? Then your SIM card can only be activated once the transfer is done. A green box around your number in the app or in My UNDO means your number is active.

Still not working? Contact us and include your SIM card number. We'll check what's going wrong.

• Classic SIM card: on the plastic card your SIM card came in.

• eSIM: in the same email as your QR code. Check your spam too.

Can't find it? Contact us. If you enter a wrong PIN code three times, your SIM card is blocked and you need your PUK code. You'll find it in the same place, or in the app or in My UNDO under MORE and SETTINGS.

Your QR code is usually emailed within the hour after your order, to the address in your UNDO account.

• Check your spam or junk folder.

• Check that your email address is correct, in the app or in My UNDO under MORE and SETTINGS.

• Still nothing? Contact us and we'll send your QR code again.

You can only scan a QR code once. Want to switch devices later? Request a SIM SWAP.

Yes. When you order, choose a classic SIM card. We ship it within 1 working day and a courier usually delivers it within 2 working days, in a cardboard A5 envelope. Shipping costs €5. It's a multi-size SIM card: you push out the right size yourself.

Nothing after 5 working days? Check in the app under MORE and SETTINGS that your delivery address is correct, then contact us. We'll send you a new SIM card.

Try this:

• Check that the eSIM is switched on in your phone settings and unlocked with the PIN code from the email with your QR code.

• Remove any old classic SIM card from your phone.

• Set the UNDO eSIM as your primary SIM card, if you have more than one.

• Restart your device.

Still not working? Request a SIM SWAP in the app or in My UNDO. You get a new QR code to install the eSIM again.

Almost always because your details don't match what your old operator has. The most common reasons:

• Wrong customer number. You'll find it on an invoice from your old operator.

• Wrong SIM card number. It's on the SIM card from your old operator.

• Wrong operator selected in your order.

• Unpaid invoice with your old operator.

Got an email saying your transfer was refused? Reply to that email with the correct details, or contact us. We'll then submit a new request. You don't need to place a new order.

Have your number blocked right away: call +32 490 46 19 99 or email support@undo.be.

Then request a new SIM card or eSIM with a SIM SWAP. In the app or in My UNDO, go to MANAGE under YOUR TARIFF and choose SIM SWAP. You keep your number.

After three wrong PIN codes, your SIM card is blocked to prevent misuse. You unblock it with your PUK code. You'll find that code:

• on the plastic card your SIM card came in

• in the email with your eSIM's QR code

• in the app or in My UNDO, under MORE and SETTINGS, at the bottom right

Enter the PUK code and follow the steps on your screen.

Just itsme. You use it to create your account and we verify your identity, without paperwork or copies. If you're keeping your number, also have your customer number and the SIM card number of your current operator at hand.

itsme not working? Check that your itsme app is up to date and try again after 5 minutes. Still not working? Contact itsme. No itsme yet? You can request it through your bank.

Then choose a classic SIM card when you order. When ordering, you enter the brand and model of your smartphone, and we check right away whether eSIM works. That way you know straight away which SIM card you need.

Smartwatches are not supported for now.

• In the app or in My UNDO: click MORE and SETTINGS. At the bottom right you'll see your NSCE, your SIM card number.

• On the back of your classic SIM card.

• For an eSIM: in the email with your QR code.

• In your smartphone, as ICCID. On an iPhone via Settings > General > About. On Android via Settings > About phone > Status.

No. There's no minimum contract period. You can cancel your subscription every month, and you can always take your number to another operator.

Yes. In the app or in My UNDO you can add an extra data bundle or unlimited texts, from €2 a month. You'll find them under YOUR TARIFF: click SHOW ME if you don't have any extras yet, or MANAGE to add or stop extras.

Need more for just one month? Then you simply pay €1 per extra GB. You'll find the prices on the Plans page.

Yes. In the app or in My UNDO, click MANAGE under YOUR TARIFF and choose CHANGE SUBSCRIPTION. Pick the new subscription and confirm.

Your new subscription starts on the first day of the next month. Until then you stay on your current subscription, and as long as the new month hasn't started, you can still cancel or change the switch.

Yes. On your own account you can order up to 7 SIM cards. You stay the main account holder: you pay the invoices and manage the settings. Your child logs in with their own number and only sees their own subscription.

There's no pause button. Contact us and we'll look together at what's possible, for example for a long trip or a stay in hospital.

Want to keep your number at the lowest price? You can switch to Zero Waste, for €4 a month.

If you cancel and order a new SIM card later, you get a new number. A stopped number can't be recovered.

Yes. You can also pay your invoice online. In the app or in My UNDO you see your open invoice under your subscription. Click PAY €xx.xx and follow the steps. You can also do this via MORE and MY INVOICES AND PAYMENTS.

Want to pay automatically later after all? Go to MORE, MY INVOICES AND PAYMENTS and click PAYMENT METHODS at the top right. Choose direct debit and follow the steps.

Yes, in two ways, in the app or in My UNDO:

• Out of bundle limit. You choose how much you can spend per month outside your bundle at most: extra data, calls and texts, but also international calls, premium numbers and roaming outside the EU. Click MANAGE under your subscription and choose OUT OF BUNDLE LIMIT. A new limit applies immediately.

• Limit for data roaming in the EU. By default, your roaming data is blocked once you've used €60.50 outside your bundle. You get a text at 80% and at 100%. You switch this limit on or off via MANAGE, NETWORK SERVICES and LIMIT FOR DATA ROAMING IN EU.

Once you reach a limit, that usage stays blocked until the first day of the next month.

Not yet. We're working on it.

Order your subscriptions online or in the app, and log in with itsme. Add your company details when you order: your account is then a business account straight away. Want to transfer more than 20 numbers? Email sales@undo.be. We'll set up your account and help you place the order.

Bringing your employees' numbers along? Have each employee fill in the MNP form and collect them. You use those details to place the order. Don’t cancel the current subscriptions before the transfer. They end automatically once the numbers are active with UNDO.

From 5 active plans you get a discount. We apply it to your monthly invoice automatically. More info on the Business page.

Cancelling takes three steps:

1. Download the cancellation form and fill it in.

2. Send it to support@undo.be.

3. We stop your number and confirm by email.

At the start of the next month you get one last invoice, for your usage and your subscription up to the day your number stops.

Taking your number to another operator? Then your UNDO subscription ends automatically once the transfer is done. You don't need to cancel anything.

In the app or in My UNDO, click MORE, SETTINGS and ACCOUNT SETTINGS. Click EDIT to change your password or email address.

In the app or in My UNDO, go to MORE, MY INVOICES AND PAYMENTS, and click PAYMENT METHODS at the top right. Choose online payment or direct debit.

For a direct debit or a new account number, you make a verification payment of €0.02. You get it back within 3 working days. The direct debit applies from your next invoice. An invoice that's still open, you pay online first.

We do that for you. You don't need to take out a new subscription and you keep your number. Send an email to support@undo.be with:

• your UNDO number

• the company name and VAT number

• the registered office address

• the name of the legal representative

• your company's email address, if it's different

From the next month, your invoices are in your company's name. You move your direct debit to your business account yourself, via MORE, MY INVOICES AND PAYMENTS and PAYMENT METHODS in the app or in My UNDO.

First cancel your subscription. Then, in the app or in My UNDO, click MORE, SETTINGS, ACCOUNT SETTINGS and DELETE ACCOUNT, and confirm. Your account is deleted right away.

You'll find more information on the Account deletion page.

In the app or in My UNDO, under YOUR TARIFF, you see how much data, call minutes and texts you have left. Via MANAGE and HISTORY you get a detailed overview, and you can choose another period there too.

Page 2 of your monthly invoice shows your usage per service.

Did you pay something you didn't owe, for example the same invoice twice? Then we automatically deduct it from your next invoice. Would you rather have it back in your account? Email support@undo.be with:

• your UNDO number or customer number

• the amount

• the reason

• if possible, proof of payment

You get an answer within 5 working days. An approved refund is in the account you paid from within 10 working days.

From €4 to €24 a month, VAT included:

• Zero Waste: 4 GB, 400 call minutes and 400 texts for €4

• Rise: 8 GB, 800 call minutes and 800 texts for €8

• Boost: 30 GB, unlimited calls and 100 texts for €18

• Wild: 40 GB, unlimited calls and texts for €24

What you don't use in a month, you take with you to the next month. You'll find all the details on the Plans page.

Your invoices arrive by email at the start of every month. Check your spam or junk folder first.

In the app or in My UNDO you'll find your recent invoices under MORE and MY INVOICES AND PAYMENTS. You can download them as a PDF there, and you also see all your payments with date and amount.

Need an older invoice, or never get invoices by email? Contact us.

After a refusal, your direct debit with UNDO stops automatically.

1. Pay your invoice online: in the app or in My UNDO, click PAY €xx.xx under your subscription.

2. Set up your direct debit again via MORE, MY INVOICES AND PAYMENTS and PAYMENT METHODS. Got a new account number? Enter your new IBAN.

A refused direct debit costs €5 in administration fees. You'll see it on your next invoice.

Your subscription is suspended when an invoice stays unpaid for too long.

1. Pay all your open invoices in the app or in My UNDO: click PAY €xx.xx under your subscription.

2. After your payment, your number is active again right away.

3. Still not active after 24 hours? Contact us.

To avoid this in the future, set up a direct debit via MORE, MY INVOICES AND PAYMENTS and PAYMENT METHODS.

• Usage outside your bundle. Page 2 of your invoice shows what for: calls, texts or data.

• A refused direct debit: €5.

• A reminder for an unpaid invoice: €8.

You can find all costs and compensations in the price list.

• Due date. You have 15 days to pay. The date is on your invoice, in the email and in the text message.

• Reminders. After that you get reminders by email and text. With the second reminder by email, we charge €8, on your next invoice.

• Suspension. If you still don't pay, calls, texts and data are blocked. Your number still exists.

• Termination. If the invoice stays unpaid, your number is permanently stopped. That can't be undone.

Pay your open invoices in the app or in My UNDO, or set up a direct debit. Having trouble paying for a while? Contact us and we'll find a solution together.

You just keep surfing and pay €1 per extra GB, up to the out of bundle limit you set yourself. Once you reach that limit, your usage outside your bundle is blocked until the end of the month.

Often need more? Add an extra bundle in the app, from €2 a month, or switch to a bigger subscription.

You take them with you to the next month.

• At the end of the month, whatever you have left rolls over.

• The next month you use that up first, and only then your new bundle.

• Whatever is still left after that expires. So rollover always applies for one month.

With Boost, data and texts roll over; with Wild, only data. You see what you have left in the app or in My UNDO under YOUR TARIFF. If you cancel or take your number to another operator, it expires.

The maximum you spend per month on top of your subscription and your extras. It applies to calls, texts and data outside your bundle, but also to international calls, premium numbers and roaming outside the EU.

Once you reach the limit, that usage is blocked until the first day of the next month. You change the limit in the app or in My UNDO: click MANAGE under your subscription and choose OUT OF BUNDLE LIMIT. A new limit applies immediately.

As a consumer, you can cancel a subscription you took out online within 14 days, without giving a reason. To do so, download the withdrawal form, fill it in and send it to support@undo.be.

The main account holder has access to all numbers and settings of the account: paying invoices, changing subscriptions, adding extras.

Other users log in with their own number. They only see their own subscription and assign their own CO₂ credits.

At the start of every month, by email, at the address you gave us. You'll also find your invoices in the app or in My UNDO, under MORE and MY INVOICES AND PAYMENTS.

Your first invoice covers the part of the month in which your number became active, plus the next full month. That's why it's usually higher.

On every invoice, at the top left under the UNDO logo. Mention your customer number and your UNDO number when you contact us. That way we find your file quickly.

In the app or in My UNDO: go to MANAGE under YOUR TARIFF and click HISTORY. You see your call minutes, texts and data for this month. Click current month to choose another period.

Page 2 of your monthly invoice shows your usage per service.

Choose based on how much data you really use. Check your usage over the last few months.

• Zero Waste (4 GB, 400 minutes, 400 texts): if you’re mostly on wifi, for a second number or for a child’s first phone.

• Rise (8 GB, 800 minutes, 800 texts): if you chat, navigate and listen to music on the go every day.

• Boost (30 GB, unlimited calls, 100 texts): if you call a lot and need more data, for example for work on the go.

• Wild (40 GB, unlimited calls and texts): if you use a lot of data and often share your connection with your laptop.

Not sure? Start smaller. What you don’t use rolls over a month, extra data costs €1 per GB and you can switch plans every month.

If you take a new number, you make an advance payment when you order:

• the price of one month of your subscription

• plus €5 if you have a classic SIM card sent to you

The advance payment is settled on your first invoice.

If you keep your current number, you don’t make an advance payment.

You pay from the day your number became active. Your first invoice, at the start of the next month, therefore has two parts:

• the part of the month in which your number became active

• the next full month

Example: if your number has been active since 15 September, your invoice at the start of October covers 16 days of September and the whole of October. From your second invoice, you simply pay your monthly amount, plus any extras or usage outside your bundle.

If you took a new number, the advance payment you made when you ordered is settled on this first invoice.

Yes. Want to support more certified projects than your included credits allow? Add an extra:

• 2 kg for €1 a month

• 5 kg for €2 a month

• 10 kg for €3.50 a month

You add them in the app or in My UNDO: click SHOW ME under YOUR TARIFF.

In the app or in My UNDO:

1. Go to SUSTAINABILITY. There you see your emissions for this month, calculated based on your device, charging and your usage.

2. Click UNDO REMOVAL and choose the project you want to support.

3. Confirm. Your credits go to the project you chose.

Want to support more projects? You can add extra credits, see the question "Can I add extra CO₂ credits?".

The first time you go to SUSTAINABILITY in the app, you get a short explanation. At the end, the app asks whether your device is new or refurbished, so we calculate your emissions correctly. After that, your UNDO Tracker is set up.

From four parts:

1. Your device. The emissions from making your device, with a difference between new and refurbished. We use the environmental reports of manufacturers such as Apple, Huawei and Fairphone.

2. Charging. An estimate based on how long your device charges.

3. Your usage. The energy the network uses for your calls, texts and data.

4. Your SIM card. The one-off emissions from making and shipping your SIM card or eSIM.

No, and we don't claim to be. A mobile subscription causes emissions too. What we do: plant a tree in our own forest in Congo for every new subscription, and support certified climate projects with CO₂ credits. Those credits don't reduce our own emissions.

With every subscription you get a number of CO₂ credits every month, at no extra cost. In the app they're called KGs. You assign them yourself to a certified climate project of your choice, in the UNDO Removal section. What you don't assign rolls over to the next month.

These credits support climate projects. They don't reduce the emissions of your phone use. You'll find which projects they are, with their certificates, under UNDO Removal.

Our own forest near Ibi Village, close to Kinshasa in DR Congo. It's fully owned by UNDO. Together with our local partner, families from the area plant acacias between maize and cassava, on dry savannah. In the first phase we aim to plant 25,000 trees.

For every new subscription we plant a tree there, and with Wild one every month. You can also support projects in the village. You can see how far we've got on the Ibi Village page.

With UNDO Removal we buy certified CO₂ credits from projects worldwide, verified against recognised standards such as Gold Standard, Puro.earth and Verra. With the credits in your subscription, you decide which project you support.

Since 2023, our customers have allocated 153.3 tonnes of CO₂ credits this way to five projects. Three remove CO₂ from the air, with biochar, enhanced weathering and storage in concrete. Two avoid emissions, with safe drinking water and biogas. You'll find the volume and certificate per project on the UNDO Removal page.

From three things: making your device, charging it, and the network that handles your calls, texts and data. That network and charging use electricity, and making a smartphone takes raw materials and energy.

In the app you see your own emissions every month. How we calculate them, you can read in the question "How does the app calculate my emissions?".

Projects from the residents' own wish list: education, medical care, equipment for the farmers and the bees. For €0.50 a month you support a project of your choice. You can also have extra trees planted, in Congo or in Belgium, from €1.50 a month.

You'll find them in the app or in My UNDO: click SHOW ME under YOUR TARIFF. You can see what's already been done on the Projects page.

Around Ibi Village there's dry, degraded savannah where we can bring back forest on a large scale. That's harder in Belgium. The families who plant and look after the trees also earn an income from it, and the acacias between the crops make the soil fertile again.

We also plant in Belgium: together with Go Forest we're restoring forest along the Amblève. You'll find all projects on the Projects page.

Yes. UNDO supports VoWiFi (calling over wifi) and VoLTE (calling over 4G). There's nothing to activate with UNDO: it works if your smartphone supports it and the feature is switched on in your settings.

Calling over wifi is handy where mobile coverage is poor, at home or at the office for example. The quality of your call then depends on your wifi connection.

Yes, if your smartphone supports 5G and you switch 5G on in your settings. You don't need to do or pay anything extra. UNDO uses the Orange 5G network.

Yes. Outside the EU your phone connects to a local operator, and the roaming rates of that country apply. Those don't come out of your bundle. So check the rates per country before you leave.

Can't call or surf? Choose another local operator manually in your phone settings, restart your device and check in the app under MANAGE and NETWORK SERVICES that data roaming isn't blocked.

Type + or 00, then the country code, and then the number without the first 0. A Dutch number 040 281 12 15 is dialled as +31402811215 or 0031402811215.

You can call and text all countries. You'll find the prices per country on the Rates page.

Type + or 00, then the country code, and then the number without the first 0. A Belgian number 0487 03 04 05 is dialled as +32487030405 or 0032487030405.

In the EU you use your bundle just like at home. You'll find the prices outside the EU per country on the Rates page.

Type the code with the number you want to forward to, for example +32486123456, and press the call button.

• When you're on a call: **67*number# · switch off with #67#

• When you have no coverage or your phone is off: **62*number# · switch off with #62#

• When you don't answer: **61*number# · switch off with #61#

• Always: **21*number# · switch off with #21#

To switch off all forwarding at once, use ##002#.

You pay for a forwarded call as if you were calling that number yourself.

You get a text when there's a new message. Call 1987 for free to listen to it. Abroad, call +32 490 46 19 97.

On an iPhone you need to enter a separate APN for the hotspot. Go to Settings > Mobile Service > Mobile Data Network. Under Personal Hotspot APN, enter: mworld.be.

Call 1987 for free and record a greeting. If you don't, callers hear "This is the voicemail of…" followed by your number. Your voicemail is free.

Getting expensive premium texts or calls?

• Send STOP to the service's short number. That unsubscribes you.

• Or block all premium numbers: in the app or in My UNDO, click MANAGE under your subscription, then NETWORK SERVICES, and switch off Premium numbers.

Call 1987 for free and choose option 4. Your voicemail switches off right away. You switch it back on the same way.

160 at most. A longer message counts as several texts: one text per 160 characters.

After 20 seconds by default. You can choose 5, 10, 15, 20, 25 or 30 seconds yourself. Type **61*+32490468787**number of seconds# and press the call button. For 5 seconds that's **61*+32490468787**5#.

• Choose another local operator manually in your phone settings.

• Restart your phone.

• Dial with + or 00 and the country code, without the first 0 of the number.

• Check in the app or in My UNDO under MANAGE and NETWORK SERVICES that data roaming isn't blocked.

Check in your smartphone's messaging settings that the message centre number (SMSC) is correct. It should be +32495002530.

Getting anonymous malicious calls or texts and want to know who they're from? File a complaint with the Telecommunications Ombudsman.

Usually your smartphone sets everything up automatically. If it doesn't work:

• Restart your smartphone.

• Check that mobile data is on, and abroad also data roaming.

• Set up the APN manually: name UNDO, APN mworld.be. On an iPhone via Settings > Mobile Service > Mobile Data Network, on Android via Settings > Connections > Mobile networks > Access Point Names.

Got a Xiaomi? Then switch off VoLTE and Carrier services, or set your device to 4G instead of 5G.

Still not working? Contact us. We'll look into it with Orange's technical team.

Nothing extra. In the EU you use your bundle just like in Belgium. Once your bundle is used up, you pay €0.10 per minute, €0.05 per text and €0.001 per MB, just like at home.

You'll find the prices outside the EU per country on the Rates page.

A protection against high costs. Once you've used €60.50 of data outside your bundle in the EU, your roaming data is blocked until the end of the month. You get a text at 80% and at 100%.

You switch the limit on or off in the app or in My UNDO: under YOUR TARIFF, click MANAGE, then NETWORK SERVICES and LIMIT FOR DATA ROAMING IN EU.

• International calling is calling or texting from Belgium to another country.

• Roaming is calling, being called, texting and surfing while you're abroad yourself.

For both, you'll find the prices per country on the Rates page.

Every country belongs to one of six zones, from A to F. Zone A is the EU, together with Norway, Iceland, Liechtenstein, the United Kingdom, Ukraine and Moldova, among others. Switzerland is not included. Check your destination on the Rates page: type in your country and you see the zone and prices right away.

UNDO uses the Orange network, with 4G and 5G. Both the eSIM and the classic SIM card work on 5G, if your smartphone supports 5G and 5G is switched on in your settings.

• 1987: your voicemail, free from Belgium. From abroad, call +32 490 46 19 97, at the normal roaming rate.

• 1989: customer service, from your UNDO number. From another phone, call +32 490 46 19 99. Working days from 8.30 am to 5 pm.

All the ways to reach us are on the Contact page.

No, and that's deliberate. Most of a phone's emissions come from making it, not from using it. Looking for another device anyway? Look at refurbished first: it works perfectly with UNDO.

Yes. In the app, when you set up the UNDO Tracker, you indicate that your device is refurbished. That way we calculate your emissions correctly.

No, not for now. The UNDO eSIM works on most smartphones and tablets with eSIM. Check your device's specifications if you're not sure.

Leave it in your device until your number is active with UNDO. Until then it keeps working. You get a text as soon as the transfer is done, and from then on you don't need your old SIM card anymore.

The IMEI number is your smartphone's identification number. Type *#06# and it appears on your screen. On older devices it's also under the battery or on the box.