You're name address on your iTunes account matches (including spacing and format) then name and address that you card is registered to ? And the card was issued by a bank in the country where you and your iTunes account ?
You can contact iTunes Support via this page (the contact methods may depend upon what country that you are in, and the time of day that is there ; there isn't a phone number for iTunes Support) : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page