Sounds like you added €12.99 cash credit to your account rather than buying a membership plan?
What does your Transactions page say about your recent payment?
You need an active membership plan in order to be able to use outgoing services.
You might want to read this to understand how 48 works because it's a bit different to some other pay as you go mobile service providers.
You might also want to read the New To 48 FAQs.
If your cash credit balance is €12.99 then you can use that to buy a membership plan.
For mobile data to work you also need your APN settings configured correctly.
If you continue to have problems then post back with detailed information so that the Community Forum can offer advice.
If you need to contact 48 support about this then see the links in my signature below.
