Faulty vechile and bad service

Today I need to share my disappointment with Nissan milnerton. On the 29th of March 2023 I bought a vehicle cash at their branch. They said the vehicle was 100 in working condition. A day after I paid and signed I got a message stating the car had problems and needed to get fixed. I got my car only on the 6 the of April 2023. On the 17 the of April my rear view mirror fell of until today it was not fixed as promised. On the 13 the of May my car started smoking. After calling Nissan they came to fetch it. After a month I got little to none updates. I even paid for a warranty to cover my engine. Now they say I need to pay in as my warranty only covers part but it was not explained to me as that when I bought the vehicle. I paid them in full trusting that I got a vehicle worth half a million rand. The used vehicle manager do not give updates and now can't even help me with my issue. Pls beware before signing. I have compiled a whole file with messages and evidence to back up my story.