Did they ship it to your home from Disney? I know we have bought big things before and for a fee they will handle all the shipping. If so, maybe they could look up where they shipped it and they would have all the info they need.
I'm not trying to make you mad, but I always try to look at both sides of the story, and you have to understand their side if you don't have the receipt. I am always losing the receipts, but if I could show them where it was on my credit card statement, I would do that in a heartbeat to get everything taken care of. If it was charged to your Mom's credit card why wouldn't you want to give them that information to get this all resolved? I know you didn't do anything wrong and you didn't steal from them, but you have to understand there are hundreds of people out there everyday that do.
Hopefully you will be able to get this taken care of