Refund - Sani Car rental waiting since the 20th September

I took a car rental on the 17th September, and dropped the car on the 20th September, when I took the car I paid a deposit of R3500.00. The rental had to refund me the amount of R3500 after 7 days, but until today no amount is paid to my account as yet. They have been telling me different stories instead of paying my money back. This is a frustrating experience for me. Please help!