***** case ignored

I rented a Mercedes Benz from hertz. While on my journey, mirror fell out. I phoned them and told them about the problem. They refused to assure me that they will pay for the cost of returning the car to them because that was not my fault. Now they want me to pay for the fault that existed before they gave me the car. On top of that Mercedes Benz repairer issued a statement saying that the mirror and mirror housing was badly damaged from a hard impact. Hertz does not want to pursue that also. I gave them the pictures i took when I returned the car that proves that the mirror and mirror housing was not damaged as per statement issued by Mercedes Benz but they are ignoring them too. Hertz is letting a ***** case go, they don't want to investigate their staff instead they want their customers pay for damages caused by their staff.