I had this annoying problem for months ever since moving out of the states but trying to pay with the same card. Best part is even after contacting SE about it they pretty much tell you it's like that to prevent fraudulent charges to your card from overseas....even if you verify that it's YOU trying to pay your sub(oh gee thanks SE for KEEPING ME FROM SCAMMING MYSELF BY PAYING MY OWN SUB).

I was finally able to ge tpast this by using the hola better internet extension(I use it on google chrome), and it works just fine now. Good luck op!