did you pay with a credit/debit card? Apple has all of these stored on file. When I traded my 4gb iPhone in for an 8gb, I told them I might not have the receipt, they asked me how I paid, and since I'm not Randy Moss and don't use "straight cash homie" they were able to help me out and pulled it right up. I don't think that will be the problem. And now I have the new receipt. So I'm good.