I want to understand that why they included both fenders for fixing tiny stone chips as if the car was involved in an accident.

Morning I have rented a car at Avis Kathu last year upon returning the car they inspected the car and it was having tiny small chips and they took all my money that I should get after returning the car now they say I must pay extra R 1198 on top of R6000 they took for stone chips. Their invoice include left and right fenders for that tiny chips and they can't explain how so they want to hand over the account if I'm not paying that money.