Terrible service

I rented a car for 5 days as part of the Flysafair deal. On return of the car, we enquired about another rental for my husband and Enver suggested we just extend the current deal with 2 more days, quoting us for the additional days. Seven hours later, cassica phones and quite rudely states that the car had to be returned at eleven. No amount of explaining can convince her of the facts and I am left feeling like a ****. She then puts through double the amount quoted on my card. When I phone her to say that is not the amount quoted, she says it is time related and if we wanted it at the quoted amount, it should have been debited when the deal was done. I am truly dissapointed in this company and do not plan to use their service again