How to resolve Xbox Live Billing issues?

I recently had to change my payment options for XBL, and added a card a couple of days ago to my payment options. Yesterday, I could play games online without problems, but today I try to login to Xbox Live and get an error message saying "Your account has been suspended due to a problem with your payment option. Please update payment information." So I check to make sure everything is correct with my card, and it is. but Xbox Live still fails to login. any suggestions on solving this?