I had the same problem when I tried to pay through debit card(not prepaid). I inquired with the bank & they had little clue what was happening. So I applied for credit card with the bank & the credit card seemed to work. It's weird how it worked for you before & it's not working now. For me it didn't work from the first time. Probably try waiting a few days & then try to subscribe or inquire from where you bought the card. If this doesn't work, maybe look for other feasible options to pay through. Tricky situation to be in. :|