Rental Rent Off

We rented a car on the 30th ad usual the is an amount of money they keep n give you after the car is back.I was suppose to be charged 2000 something for my rental as per agreement but I was debited 3000 something for the rental alone then they kept 4892 which I still haven't gotten basically I'm being charged 8000 for the rental car for just 4 days. I called but no one is giving me an answer when am I going to get my R4000 back