Custom Truck

I had Custom Truck install a sprayed-in bedliner for my truck. In order to apply the liner, they removed the rubber seals from the tailgate by cutting them off in several pieces and then throwing them in the trash. As the truck is 20 years old they cannot find replacement parts from the manufacture and I am now left with a truck missing body parts. Their response has been that I don't need the rubber seals. It is as if I had taken a car to a body shop for a paint job and they removed trim pieces in order to paint the car and simply threw away the trim pieces; returning the car to me painted but without any factory trim.