It is more than likely your bank blocking the transaction since most of them bill from China. You may want to contact your bank and make sure your card is not locked down now. Most sites tell you that you can not use a card unless it is a real credit card. I had this problem once, started using PeachDS and never had a problem since. Whatever you do though, don't mention what you are trying to buy to your bank. Tell them it is computer parts or something.