Unhappy with Avis!

I am extremely unhappy with Avis. As events occurred, when collecting a vehicle for rental there was no one that took me to the car to assist me with an inspection of the car. On return of the car, Avis pointed out that there was a cut on the tire. I explained that no one did an inspection on the car when I collected it, so as far I was concerned the cut on the tire was preexisting. Avis is now trying to make me accountable for the damage without any acknowledgement as to their service delivery failure. Furthermore, when returning the Car, the inspector showed me the cut and said that I should write on the return card that there had been no inspection prior and that if I did that everything would be fine. In back-and-forth emails with Avis, I was then told that the damage was to the front rim of the car and that according to their MOBILE DAMAGE MANAGEMENT SYSTEM the damage was not noted. Then I received an email stating that they had made a mistake and that the damage was to the rear wheel of the car. Avis couldn’t even get right which car they were holding me accountable for. How can I trust their so-called system if they cannot even get the correct car right?