terrible service and false information

I did a booking online for a car. I paid the amount of R2745,80 online. When I went to pickup my car I was notified that I will have to pay for an additional driver, and that my excess on the insurance is very high, I agreed for an extra fee that I will "upgrade" the deal. Another amount of R2830,90 was put on hold on my credit card. I asked the advisor why so much money was taken he said that the difference will be paid back to my card upon the return of the car. I was surprised today upon the return of car, that another amount of R6245,24 was deducted from my card. R11822.15 is a bit much for this vehicle I think. Upon my return to Rand Airport today I asked the agent about these amounts and he told me it was a mistake made. He will notify customer care amount this mistake. I asked before I took this vehicle about the charges, why do I have to be surprised afterwards about these amounts? Is this not *****? And why when you phone customer care do they advise you to sort out the problem with the branch. What is the purpose then of customer care?