DON'T USE AVIS O.R. Tambo

After renting a vehicle for one week, I turned the car in after just filling up at the ENGEN petrol station there on the airport grounds to the "First Click" in the amount of R347.45, approx 15 ltrs then drove around the short distance of 2 kms. I then later get an invoice of R83 for refill of 4 ltrs with a fee of R25. After my initial query, I was told that there is a grace of R50 when they do a turn in check, which normally I wouldn't make an issue of but in this instance, there is NO WAY that I/car used 4ltrs in 2 kms and questioned whether the car has mechanical issues or a human factor upon turn in on their end is the problem. Eventually started corresponding with the "Manager" Petrus van Biljon who twice insulted me by saying I didn't "entertain" that the station attendant didn't properly refill to the "first click" then when on a rant about wanting to see ALL my gas receipts for the 764k I put on the car and it "didn't add up" that I put in R347 & 15.3 ltrs. and THEN he MIGHT issue a refund. Actually questioned my query with fuzzy math regarding amount of ltrs & kilometers I put on in total, not even thinking that I had put at least two full tank refills in the 764k during my week use. That they didn't look at the gauge when filling up to the "first click", something about how many thousands of rentals occur weekly by Avis and that as the amounts in question were in my opinion small, it would somehow bankrupt Avis if they ate the cost each time. Yet being a hypocrite as Avis, a large corp quibbles about a small amount. TERRIBLE customer service, TERRIBLE service and in all my 50 years of renting vehicles I've never been directly insulted, questioned even after PROVIDING A RECEIPT AS proof showing time/date amount paid and quantity that matched within 10 minutes of turn in time/date. I rarely use Avis as a choice due to overall cost of vehicles but in this instance, it fit my budget and need. Have most times use Budget or Dollar but I don't think that the issue here is the company but the representatives and office location that is PROBLEM and gives the company a Black Eye, bad name! I will NEVER entertain the thought of using Avis again even IF it fits my budget or less expensive!