Holding deposit

I've hired a car with Avis Centurion on 22 April 2021 and it was returned with full fuel tank on 24 April 2021. They held a deposit of R10 000.00 the day i was taking the car and i have not received my deposit even today (6 April 2021), when i called them they keep on saying they sent the notification to my bank to release my deposit and it will reflect within 24 hours. It is really frustrating what they are doing. AVIS please release my deposit!!!