Overcharge for repair to AVis rental car

I am a preferred Avis customer for the passed 5 years. On 6 October 2020, I rented a Hyundai Tucson, scratch the head light cluster, took photos and reported it on return of the vehicle. The damage was R19000,00 on the invoice. This amount was unacceptable to me. I am still waiting for response despite several emails where I requested the repair document or breakdown of the cost from the repair company. Now they refuse to rent me another vehicle until this is settled. Rental invoice ref number E***.