poor service

i bought a vehicle on the 26 October 2023, and returned it on the 30th of October 2023, because of malfunctioning of a gearbox , wind screen cracked, light not functioning and some cover missing . I have lodged a complaint to cancel a contract and i was told that only MMU Motors dealership can cancel a contract, MMU motors want me to change the car i said no, cancel the deal. i don't even have a copy of registration certificate of the vehicle. and the car is still at the dealership I'm paying for nothing.