Trying to complete a purchase on the Ubuntu One Music Store...

...so that I may take advantage of the 6 months free music streaming and 20 GB of storage. No matter which way I input my credit card information, and I have tried every possible way, I get an error stating that the card information is invalid. I even when to 7digital.com's site, signed up for an account, and tried to add the card there, with the same result. The balance is currently zero, as I paid it off last week, so that it not the issue.

Any suggestions?

are you sure your using the right date. There is a space for start date and a space for expiration date. Only use what applys to your card.

I have exactly the same issues. Trying to insert a visa (debit) card number that is accepted by amazon, google, paypal and ebay, and I always get "Card number is invalid" whatever I do, when trying to add a card to my account.

Had to use Amazon music store instead...