Unsertiesfied customer

I justbought a car at kia randburg 2 and halfs ago. Konw theres brakes that wich need to be changed they at 30% costs R3500 and splash tray costs R5. 500 I must pay for. And I was not told about this before I toik the car and they say cars ars certified how if they have such problems and hidden from the customer.