While our tunnel layout is different than what the OP was talking about, I will explain our system. We have disclaimer signage at each terminal that states we are only responsible for vehicle damage related to our equipment. We are not responsible for damage to mirrors, antennas, loose fitting chrome or paint, aftermarket wheels or tires, non OEM equipment, or vehicles older than 7 years. We are also not responsible for damage due to collisions or braking in the tunnel.
Whenever we have an accident or a complaint about scratches or damage to a vehicle, we have a process. The manager looks at the damaged vehicle and then looks at the entrance and exit cameras. Entrance area has three outdoor cameras as well as four prep area cameras. Exit area has two cameras by the tire shine as well as three outdoor cameras. We also have cameras in our vacuum area. Almost every single damage complaint has been found to be pre-existing damage to vehicles or damage as a result of dragging vacuum hoses over vehicle surfaces.
If it is found to be our fault for damage, we would send your information to our insurance company or have you get at least two quotes for repair. After we receive the quotes or our insurance company decides to pay out, we arrange payment to the customer.
In my almost 10 years of washing, I have only seen one incident where we paid out and that was because a former employee didn't send enough rollers behind the vehicle at one of our older locations and the roller actually pulled the vehicle out of the conveyor into an arch leg.
For OP, I would recommend looking for disclaimer signage at the wash entrance and keep trying to get hold of the owner. If they don't respond back to you, you might try filing a small claims suit or contact the BBB.