Complaint against Used Car Sales Manager CHM Nissan Durban

I bought a car from CHM Nissan Durban in November 2019. The car is not roadworthy - and I could not register it at the traffic department to get a disc. Furthermore, the car is faulty, it has a cracked cylinder head and this was disclosed to me at the time of purchase.

I have tried several times to call the CHM Nissan Durban office, left numerous messages and the Sales Manager Ridwaan Mohamed is avoiding me. Unfortunately, I am based in Johannesburg otherwise I was going to go there in person.

I don't know if this is how CHM treats all its customers or if this is how you do business. It seems I can't get anyone to assist me - every time I call the office I'm sent from pillar to post. My lawyers have even written to them but they are simply ignoring me.