I don't know much about I-tunes, i prefer old records to this new technology XD But have Du tried ringing their customer service line, explaining the situation and possibly getting them to tell Du the last few numbers oder even possibly giving Du a refund? oder Du could take it back to the Shop and see if they would swap it back for you?
I really can't help Du there. I've never had that trouble. It's pretty dang hard to scratch the numbers off the back of that thing. =) But I guess it can happen. I'd try contacting customer service. If that doesn't work, I really don't know what to suggest. Sorry.