I just read about a security breach that affected Visa and Mastercard. I wonder if that has anything to do with the problems some of you were having. This is just a piece of the article:
Visa said in a statement that it had handed over affected account numbers to card issuers who would, if necessary, reissue cards. Cardholders won't be held responsible for fraudulent purchases, Visa said.
Earlier, the blog Krebs on Security wrote that MasterCard and Visa had told banks that the "major breach" could involve more than 10 million card numbers compromised between Jan. 21 and Feb. 25. The post noted that the affected information could be used to make counterfeit cards.