This is about 4 - 5 times over the years I had someone claim that and I have never answered them back or bother to try to get in touch with them, if you did have there car buffed, everyone and there brother would be there claiming that happened, and how could they prove there were no scratches before using the brush? It would be very difficult to prove, even if it did happen and I doubt it did. There are so many if's.
I don't like posting a phone number there but I probably should, maybe check into the google voice thing, I didn't know you could do that, and yes it probably is a used car, don't know why you would use a foam brush on new paint.
I wonder if they cant get in touch with you how they would find out who your insurance co is? I'm sure there are ways.