I too got the same problem. This is due to mismatch of your billing address that you provided and that is originally on your credit card or due to Abbrevation of your address.
I mean to say, If you abbreviate your address for example, If you type TWP instead of Township, this problem may araise. I faced exact same problem. When I typed my address in full with out any abbreviations, then it worked fine.
I called the customer service and what they suggested me is to try with another credit card for my purchase.
It ws your post that I read but, somehow, I couldn't find it again. I actually didn't do what you did. I put my sister's address during for the billing just so I can get to the payment section and put my credit card info in. When it asked me to confirm my billing address to make the final purchase, I went back and changed it my address and it worked fine.
Thanks so much for posting though!