DOLLAR THRIFTY END UP CHARGING AN ARM AND A LEG

I recently used a "broker" endorsed by thrifty. The booking was easy enough but when I went to collect the car I was met with a 10 000 holding deposit, I couldn't change the booking according to the sales lady at thrifty so I had to cancel the booking to get the cheaper holding deposit. So the initial booking was 1500 and the subsequent charge was 2200. This is 3700!!! for four days !!! I can rent a merc for that price this is totally off the charts. I want the 1500 refunded. add to that I contacted the Namibian office and they gave me the lame excuse that it was clear NO IT WAS NOT CLEAR you are a clown sir. I will never use these services again if this is not resolved properly.