Avis Car Rental - dishonest (Bogus scratch claim costs €500)

We rented a car for 4 days in Dusseldorf, Germany. The costs was reasonable and we upgraded upon arrival. Upon return of the car, the attendant claimed there was a scratch above the license plate. In order to find the 'scratch' he had bent down on his hands and knees. My husband told him we did not scratch the car, and the scratch he pointed out was barely visible. The attendant told my husband that it could probably be buffed out with no charge to us-we took pictures. A week later we received an invoice including €500 for repair of the 'scratch.' We submitted a claim with Avis along with our pictures. We were told we should hear back in 30 days-we haven't heard anything. I have emailed the claims department twice with no response. We have insurance to cover the costs of the scratch, however, we shouldn't need to repair a so-called scratch we did not put on the car. We will never use Avis and will be sure to caution others when considering them. We have found them to be dishonest and unhelpful. Our insurance company was not surprised and relayed to us, this was common practice with some companies in Europe. Coincidentally (or not), my husband's credit card number was obtained and fraudulently used. This happened while in Germany, and he only used his card at Avis. Hmmm. Renter beware!