European rates

I made a booking online to fetch the car at the PE airport Europcar branch.The booking was from 19/12 - 21/12,the quote I received was for R395 a day for group B.When I arrived at the airport I asked the guy who helped me if I want to extend what do I need to do,he said I must just call the branch.He said nothing about different rates as my original booking fell on weekend special.The guy asked for my credit card details I used to hire the car do that they can deduct R835.He just said it will cost that amount.Even then nothing was said about the different rates.I returned the car on 22/12.I received my invoice and I saw that the daily rate is R509 which was a shock to me because the quote said R395.The total bill was R1698,the amount that was held in my CC was R5598 and due to me is R3910.The R837 is not showing anywhere in the invoice as if it was paid.I phoned customer service the told me that I was charged daily rate not weekend.I didn't even know they different rates until she told me when I was querying the R509 rate.Im ****ed because they should have explained.I was hiring with them for the 1st time I don't know the rates and weekends and all