Expired Card cannot verify, update or delete
My card recently expired. iTunes will not let me update card or delete old card because I have to have one card on file. I cannot verify old card because it is no longer in use.
Try adding the new card and removing the old one via https://appleid.apple.com/account/manage
If that also doesn't work contact iTunes Support and see if they can help you do it : http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)