R6000 BLUNDER

i hired a vehicle on the 12th Dec 2020, i had it for +- 3hrs and returned the vehicle with a full tank and no damages. A total of R7500 was frozen from my account, R1500 released, R6000 wasn't I have now been inconvenienced I can't do my Christmas shopping. I have 3 calls to resolve the issue. Can someone competent enough resolve this NOW!