Your post isn't really clear.
Are you trying to add €20 cash credit to your account?
What happens when you try?
Any error messages?
Or do you already have €20 cash credit on your account and you want to use it to pay for something?
A membership plan perhaps?
If so then you should get the option to pay using it at checkout time.
See here:
The real sweetener is that you can purchase your plan from your available credit balance, so long as the balance covers your full plan cost.
What happens?
What do you mean by "could you return this money to my account"?
Do you understand how plans and payments work?
If that doesn't help then you'll need to explain/describe your issue/question more clearly and in more detail if you want assistance from the Community Forum.
If you need to contact 48 support about this then see the links in my signature below.
