Europcar not releasing my deposit for over a month

I rented a car from them in Durban on 27 February and they put a hold of over R5000 as a deposit and it's now a month later and they still haven't released it!the credit card company said that they have banked the money instead of releasing it. when I called Europcar 2 weeks ago they said it will be released but now I called and they say my credit card company must do it! absolutely rediculous so frustrating