Was sold a defective car

On the 14th of December i bought a car from Auto elegance in Pretoria Wonderboom for R125 500, on my way home i noticed that the gears where not shifting perfectly then i decided to take the car back to the dealership the next day, on my way to the dealership the car gave me an on board fault which kept on flashing as it had stopped changing gears and was now on limp mode. i slowly drove it to the dealership to show them and got one of the managers who was very rude and arrogant...saying if i didnt buy the vehicle warranty its not their problem, after sometime he cooled down and the fault cleared and he promised me that such faults do occasionally appear on cars that have been sitting for a long time on their sales floors and he promised me after driving the car around the fault will disappear. I took the car home only to have the fault again two days later, i called them and they did not coperate then i took the car to the garage that it has always been serviced by the previous owner and the garage pulled out the service history and showed me that the car was due for a gearbox service as it had never been serviced at 160000km, the garage charged me R6500, the dealer wont pay.