Have you checked all the info, payment acct + other, at http://commerce.microsoft.com ?
If so, suggest you contact a Billing Agent. You can choose Option 1 after finding your country's support line: See http://tinyurl.com/XBLnumbers ...
but a faster way to speak to a Billing Agent is to go to http://xbox.com - sign in there if you can - then go to http://support.xbox.com/contact-us?xr=footnav#0:2:5
Click on Request A Call and type in a few lines explaining your issue and you will get called back quicker than if you waited in queue on hold.