Faulty Gearbox

I Bought Secondhand Polo Playa Automatic 2007 Model in Mastercars Dealership in Menlyn ,Garsfontein Road Pretoria In 30 Dec 2014. Towards the end of Feb , i experienced problems with Gearbox and i notified the dealeship , they asked me to bring it back to be checked, after inspection and test driving it was found out that it had what is called pulling delay. The car was taken into their workshop to be fixed and new gearbox was sourced out, the total cost was + - R30K , My warranty was prepared to pay R8000 of which there is a shortfall of R20K.<br> So the dispute came when the dealership wants me to pay half of R20K of whick i refuse, i found it unfair to me for them to say i am also responsible for the damage, how possible is that. Its ***** for them to sell me knowinly the car that have mechanical problems, taking ******** advantage of me. Presently the car is parked at their workshop gathering dust while i am paying monthly installments together with insurances. I am getting raw deal from this dealeship. when you send emails to them , they hardly respond.<br> <br> Please help me.