What exactly do you mean by "activate my membership"?
I presume you mean that you're trying to buy a membership plan?
What happens when you try to make a payment?
Any error messages?
Does it make any difference if you use the web interface instead of the app - or vice versa?
When were you able to successfully buy a membership plan last?
Is your payment card still valid?
If you need to contact 48 support about this then see the links in my signature below.
