Poor Service - First Car Rental

I booked a flight with FlySafair for Saturday the 22 May2021 clicking the option for car rental when i arrive at the airport. Their partner is First Car Rental. I received a request from First Car Rental to make payment for the booking which i did My credit card was debited by them on the 18 May 2021 for the amount of R463.00 When i got to the airport they wanted a holding amount of R6000 which my card would not allow so i had to cancel the booking which i did and received a cancelation printout ( on demand i eventually received this) and was told by the assistant on duty that the refund would be done within 7 - 10 days . Well this has not been done and when i phoned them yesterday ( 3 June 2021) i was told i will not get a refund as i never paid any funds to them. I have checked with my bank and they were paid and no money has been refunded to me. This is the story . I used another very well known company and the hold on my card was only R2000 . How R6000 for an entry level vehicle at First Car Rental.