Incorrect billing

Good afternoon. I recently rented a car for 3 days between the 2nd and 4th January 2018. I did take photos of vehicle, when I arrived at Avis in Strand Cape Town my rental car was not ready. I was the upgrades to the grand i10. Unbeknow to was that the vehicle had a scratch on the bottom front and I was made aware of this when I returned the car. Now I have been advised that I will not be refunded with an amount of R1400.00 because of this. When I got the vehicle I found the following:wheel cap had a scratch, scratch on bottom on the not, side door there was a sent. I took vehicle from Avis in the Strand and returned same to Cape International Airport. Someone is lying to me her. This is the first time that I have rented out a vehicle.