Poor poor service

I bought a car in this garage about two months at NTT ISIZU Newcastle . It was a demo with about 4200km on the clock a Nissan Qashqai 1.2T . From a sales man called Mlindo’s and his boss/manager called Emmanuel have experienced problems with the car from day one till today , there is a bad smell coming out of the air conditioner of the car, very bad smell of petrol when I switch on my ignition , you will feel the smell of petrol the whole yard . The car jerks in low gears especially when you climb a speed hump. I’ve Phoned these people several times without any help. Their service is very poor I would like to receive feedback very soon from top management.