Given a damaged car and they charge me R1360

I rented car at Cape Town airport given Chevrolet Avio ND 489 887. The car had lots of scretches on the body and tyres. I took it with consert but the agent said it is good deal since I booked a class B and the car is class C. On the return of the car with inspection I was told that everything is fine and all my holding deposit was returned to me. After few days I received invoice starting that they are debting my account R1360 for damages no explanation and they took it just like that. I e-mailed them but they never bothered to respond me. They are bunch of ******* that do not care about people and indent on enriching themselves.