Sani Sixt did not return my deposit

I rented a car at Sani Sixt Cape Town airport and I made a credit card deposit which was supposed to be returned 3 days after returning the car. After not getting my money in 3 weeks I called the Cape Town airport Sani Sixt and I was given contradictory information about when I’m supposed to get my deposit back. And after that, when I try to call them to get any update they are not answering my calls. I suspect my number to be flagged in their system.