Horrible service from AVIS

I rented a car at OR Tambo on 15 May 2018, a holding deposit of R1450 was kept for the rental Rental Agreement No: ********** 81. On 25 May 2018, I returned it with full tank of Petrol. On Monday 28 May 2018, I called Avis about my holding deposit, I spoke to Dumisani @ Customer Service who indicated that the deposit will be released in 48hrs. On Wednesday 30 May 2018, instead of receiving the deposit, I found a deduction of R914.70 by Avis for fuel and tollfees. Why, because someone at the airport didn't do their JOB - to confirm if the car was filled up. What did I get back from AVIS, an apology and no refund, I am told about processes that will take 5 working days before the refund is made. Till today, I have not received my deposit. It has taken telephone calls between Monday and Today with 5 different consultants (Dumisani, Njabulo, Marisha, Funeka (the 4 @ Customer services) and Yolandi @ OR Tambo). And still no refund of the fuel money and the deposit. Do I want to do business with AVIS again, NO! and will I refer anyone, NO! DID THEY TRY HARDER for me, NOOO!