Michael,
I do not see a problem.You paid through paypal so ypu have a paypal receipt showing you paid for the engine on X date and to whom it was paid.That is your proof of purchase.
Just follow the procedures I gave you. You can scan the paypal receipt and attach it to the email. If you are having a problem please call and I can walk you through the process. 804-270-7635 We are always here to help.