Hi, i have same problem here. I've opened 2-3 tickets about this error but still no responses. The owner of credit/debit card, in this case 'visa electron' is my brother, but there are no differences in my billing address and the card i am using, it's the same. But i don't think the problem is that because i am paying wow and itunes since years with that. Now remaining 12 days my free period time ends and i wouldn't like to buy prepaid card to continue to play. Also i've read news from SE that if you don't register payment method within free time ends they are going to delete your ID. Sounds like a crazy thing! Maybe the problem is related that the card is empty? Maybe first time they check it and obviously the card need at least 1-2€ on? Anyway sorry for my english, i am italian.