Unfair charge for damages

I rented a car from Woodford end of May. I only used it to drive from OR Thambo to my friend’s house and back. When I returned the car 2 days later, the guy said there were a few scratches. I thought he was making a joke and started laughing as I knew nothing happened to the car while I used it. But he showed me a few small scratches on the hub cap (which you could see was old) and underneath the front bumper. Which would have been caused on two different incidents in two days while standing on a drive way. There was no inspection done when I collected the vehicle - the consultant advised me of this and said that if I see any damages I must just make a note on the inspection paper they gave me. The car was parked in an undercover parking garage and when I walked around it I did not see the small scratches and did not look underneath the bumper (not an expert in how to inspect a car in that much detail). They charged me for the damages and said that the car was inspected twice after the previous renter. I know for a fact that the damages did not happen on my watch. If they don’t inspect the vehicle with me, I can not be held accountable. But they had my credit card details and just deducted the damages and that was that. I have made use of them many times, but will not use them again in future.