Bad faith Avis

I rented a vehicle from Avis Minerton from Monday 15th January and returned it this morning to the same agency. On Monday the vehicle I originally intended renting was not available even though the booking was done a week in advance, I accepted that. The agency then gave me a VW Polo, which is a detestable car in the first place but as I was in a hurry I accepted it. I did a walk around of the vehicle and noticed a chip on the front passenger door, I checked the rest of the car which was full of light swirls and scratches but since the car was still relatively wet from washing I did not pay that much attention to it as the car appeared in good condition. However on return this morning the person who originally helped me was not available for the hand back, and the lady who then did the walk around picked up a scratch between all the other scratched low on the front bumper and proceeded to call the manager and they then blamed me for the scratches, The car was in exactly the same condition I got it in, I drove less than 200 KM in this car without any incident yet the staff at this branch impugns my character by accusing me of damaging the car. I will never rent a car from these schlemiels again.