Rented a Sedan Car, 8 hours for R2 311.79

I rented a sedan car, AVIS charged me R2311.79, which is the total rent for 6 days. I returned the car after 8 hours of rental without any damage or problems. It has been over a month now and they still did not repay me the outstanding 5 days rent amount. I phoned them to find out what the problem was and they apologised and said within 24 to 48 hours the repayment would reflect. It's been a week and I have not heard from them again and still no repayment has been made. Next time I will rather take a taxi in stead of renting a car at AVIS.