Help with Microsoft Points?

I'm trying to add MS points to my account via credit card. 500 to be exact, but none of my credit cards are working, every time i go to add them, i get a message saying "Can't authorize selected payment option. Please select a different payment option or add a new one." I've tried this with 3 different cards and i got the same message evry time. Can anyone help?? And i've tried it again after 3 or so hours.