Sold a second hand polo vivo that was damaged

My mother bought a polo vivo from Zido cars in Kempton park, for my sister who was a first time buyer. when i drove the car the brake pads were worn out, the ignition was not working and the tyres were also worn out. we contacted the dealer to fix the brake pads, they took the car in and the car was still in bad condition. they also sold this car for R120 000. we called them to let them know this car is in bad condition and they must change to a better car, nothing was available in the showroom except for a 2009 Toyota yaris which the bank could approve because it was older than the polo vivo. they then told us that there is an aveo is available which we took as there was no way we could take this car and trade it in with any car dealer yet alone sell it to anyone. they told us before we can release the car i needed to pay R3000.00 of which i did.i feel this dealership has taken advantage of us and would like them to be brought to book.