Unhappy customer

On the 30/10/24 I rented a car from Sani car rentals at OR Tambo. I was told to pay R3800 from my credit card in addition to the rental fee. The R3800 was said to be insurance just in case something happens to the car and they told me that the money will be returned to my account if all is good. I returned the car and it was inspected and no fault was found. The only thing that I did not do was to fill up the tank but they took the money from my credit card which I did not have a problem with. The problem I am having now is that the R3800 has not been returned to my credit card!