Buy from a dealership that will hand you the key and take responsibilty of all the trouble you will encounter

I bought a Mercedes Benz from Lexus Fourways on 11 August 2020 and the service I got is very bad and I have complaint about a disturbing noise within the car. I took it back to them on 22 September and on my way it rattle again. I told the salesman & he suggested that I take the car to Mercedes and they charged for diagnosis and Lexus refuse to day for that. I then took it to them on 23-26 Nov and they did nothing instead the boot sign was always on and the noise still there. I wrote an email to the principal dealer on the 9 Dec and he did not respond & the passenger seat is bend to the hand rest it is also something that courses sound. I'm paying for the car that my dealer cannot assist me at All. underneath the drivers seat there is a cover missing that was in the car when I brought the car on the 23th. People need to be careful when buying a car from other different dealership, like buy Mercedes Benz from the make unlike what is happening to me now.