No holding deposit refund- 6 weeks later

I rented a car for a month in November 2014. I returned the car on 21 December 2014. Some 6 weeks later and my holding deposit of R5500 has not been released to me. I then used their services again in January 2015 after being assured my refund was forthcoming. I again paid a holding deposit of R5500. It has been two weeks since I dropped this vehicle off and I am R11000 out of pocket. BOTH HOLDING DEPOSITS have still not been released on my credit card. I have personally been knot the Sandton branch 3 times and have phoned them on several occasions. I get the same response of \sorry sir it hasn't been actioned yet but I have instructed accounts to action the refund". This is disgusting service. My advice would be to steer well clear of this company. """