Bad customer service

I have purchased kia rio 2012 model with GM McCarthy Menlyn branch, I have two with the car, 3days after i bought the car i got stalked i called them and they tookthe car and changed the battery, secondly i complaint about the gear changer that is not covered and since then they have not fixed it, currently iam setting witha car that is shaking when i drive, smokes too, i went to GM McCarthy and the GM was closed down, i called there callcenter and i did not get any assistance from them, they are just taking me pillar to pillar but with no help, i had requested them to tell me were i should take the car because i will like to cancel the deal with McCarthy because they are failing to help me. I can not be paying for the product that i am not happy with