Be careful before booking a car with Dollar Thrifty

I booked a car at Dollar Thrifty and the consultant Yunesh made the booking, he told me the deposit will be R3500.00 plus the rental amount of the car for one day. When I got to George Airport, I was told my deposit will be R12000.00 because I am paying by debit card. Not once did Yunesh ask me or informed me that I need to pay by credit card for the R3500 to be accepted. Standing in George and I need to get to Cape Town, I had no other option but to make a plan and borrow money from my sister to pay R12000 instead of R3500, a whopping R8500 more than what I budgeted for. The lady in George told me that the payment method stands on the e-mail. Really? Why was I not told or asked how I would have paid the deposit? I accepted that the information given to me was confirmed in the mail. The more I told the lady that I was not informed of a price difference of R8500 the more I received an attitude of "it is what it is".