I had a incident with Economy cars (Herts) while renting a vehicle in Johannesburg

I had a incident with Economy cars (Herts) while renting a vehicle in Johannesburg. Hertz failed to do a pre inspection of the vehicle and when the vehicle was returned they highlighted a perceived dent in the vehicle and subsequently removed a large amount of money from my credit card without my authorization. When returning the car i was showed where to sign and was told on the reverse of the document to indicated no incident took place and that car was received as is. I have now been penalised for this perceived damage. Hertz have indicated i signed acceptance of liability however have failed to show the reverse of the document showing i do not accept liability. I have a picture of the perceived damage and cannot see any form of dent in the fender. I would not use Hertz going forward.