Unfair fine

My insurance ordered a vehicle for me at Avis for a month. I am insured for a 2 month car rental period. When the month came to an end, I tried to communicate with my insurance without success. Eventually I requested the brokers and they duly assisted. When I returned the vehicle I was fined R643. I contested the amount, called the insurer and we agreed that the fine will be waived. That did not happen. I complained to the brokers and they requested for documentation of my payments from Avis. Avis has not provided the information after more than 6 weeks. The fine has also not been reversed.