I understand Native Son has had problems in the past, but I am just not sure on this one.

I tend to think the form we filled out with the car rental company wasn't shredded or disposed of properly and our information ended up in the wrong hands - the impersonator.

Again without AMEX letting me know the questions they ask to identify a card holder it makes it hard to determine what information the impersonator used. Both companies were privy to similar information but the car rental company had all the information neatly written out on a single piece of paper.