What exactly do you mean by "not able (to renew membership)" and "top-up can't see my new balance"?
What exactly happens when you try to buy membership?
What goes wrong?
Any error messages?
What does your My48 account say about your current membership status and recent transactions?
If you need to contact 48 support about this then see the link in my signature below or email them at support@48months.zendesk.com
