non refund of deposit

I rented a vehicle on Friday 28 August 2026 and they processed a deposit of R9900 on my credit card. The vehicle was returned on Sunday 30 August 2026. It was inspected and found to be in order and I had filled the tank just before returning it. Despite requests my deposit has not yet been returned. When hiring with other companies, they block an amount on your card, but don't physically take the money and then simply release the block. This seems like a **** with them keeping funds much longer than necessary.