Double Charges & bad communication!

We rented two vehicles over the weekend while in Bloemfontein. We had arranged for the vehicles to be dropped off at the Tempe Airport. The branch manager met us at the airport & we had to go to the Hertz Office to complete the forms and supply our credit card details. They deducted an amount of R4066.00 per vehicle which would include the cost of the rental (Quoted R168 pday). The drop off arrangement was for us to leave the vehicles at Tempe Airport since the downtown branch was closed on a Sunday. We were told to leave the keys with the reception of the Airport. When we arrived at the airport we found that the airport's reception was closed.We then proceeded to lock the keys in the trunks of the car with the understanding that the branch would have the spare keys. On Monday when i informed the manager of the situation he said that i would be charged for an additional day of rental. On Tuesday an additional amount of R351 was charged to my credit card. then on Wednesday there was another R4067.00 charged to my credit card!! I have spoken to the manager, which says his superior said that the extra charge must me levied. The customer relations person i Spoke to (Nadia) informed me