Avis overcharged me - on fuel.

I rented a car on the 6th of August 2022 from OR Tambo. I returned it on the 7th of August 2022 . The car had at least a half tank worth of fuel, however when I got my invoice I found out that I was charged for a full tank of fuel. The fuel tank has a 45 litre capacity. On the invoice they wrote that they put 45 litres of fuel. That is not possible. I called the customer care , 3 times already. I was promised that it would be sorted out but I’m still waiting. Today it’s the 15th. You pay for a service, but a company this big takes more than what they are supposed to and now I must beg for my money, worst part I still have the authorization hold on my credit card. From my knowledge of having worked in the banking industry for over 10 years, authorization holds are released by the people that put them there in the first place and it doesn’t take 30 days. This is just disappointing service.