Being cheated and **** to by the sales person

I went to look for a Hyundai ix35 for my parents, I specifically made it clear to Tanya that I didn't want residual because that's something my parents didn't want, Tanya agreed, we then decided to change from a manual to an Automatic and the installment increased by a R200 from R5.500 no residual mentioned I even asked her if anything has changed other than the installment and she said no. Now today she went to deliver the vehicle in East London and she is telling my parents about residual which we never discussed. I'm so disappointed and heartbroken how could she take advantage of me and my parents like that. Why didn't she disclose everything, she waits till they travel all the way from Lusikisiki and she knows they really want the car. Wow Hyundai if this is how your sale's people work it's very unfair. My parents never budgeted for the money they are expected to pay now. Never and ever again. This just ruined my day