Sold damaged car and no resolution from dealer. (

I purchased a used vehicle two months ago via CMH Nissan HIllcrest and they failed to disclose car was accident damaged. I was having rattle issues and took it to the Renault service centre as car under warranty and report came back that car was in an accident. I sent this report to CMH Nissan and they are denying it and after numerous back and forth correspondence the principal dealer calle dme up and agreed to send car to a renault approved service provider who only checked the body and confirmed work has been done on the body. But are refusing to do a mechanical diagnosis to refute Renaults report. They are still denying car was in an accident and want me to just accept this. My issue is firstly, body work on car was not divulged which is breach of the contract as per the CPA act 2008. Secondly if you are so convinced no accident damaged car why are you refusing to do the mechanical diagnosis report which costs about R1800 . I am being asked to do this report. What poor service and looks like the dealership below par. I have contacted MFC who is helping me with this issue but at a very slow pace. I am now stuck in abattle on my own. Have also forwarded my complaint with all supporting docs to the various ombudsman and credit regulators. but they take 30 days for aresponse or outcome. In the meantime I have a