Had a 3 day Avis car rental in Dallas, using a code from a business. I purchased all available insurance except LDW. I had a fender bender the 2nd day, and finished the rental with the car. Avis is now charging me $800 including the in-house repair, fees, and loss of rental time for the vehicle. They claim I am liable because when filling out the Avis accident form, in error I checked the box that I was using the car for personal use instead of business use.

Anyone have any "constructive advice" how to go forward.