I had the same problem mate. Signed up then a year later decided to use the account but during that time i bought myself a new PC meaning i had no files on my new machine. When i went to check out it mentioned a Payment Key. Simply contacted them by Email and waited for a reply. Can't remember exactly how long it took but it was a good week or two.
They will send you a new key. Currently checked out $50 but they hold on the money on new accounts for xx amount of days. Hopefully ill have it in my paypal soon.
Ben