In your subscription, you have a certain number of minutes, SMS and mobile data. If you use more than what is included in your subscription, you can choose to purchase an additional add-on.
Here are our optional add-ons that you can purchase:

You can activate these add-ons in your app or in “My account” (https://wsc.undo.be/). Under “MY TARIFF PLAN”, you can click on “SHOW ME” to activate the add-ons.