Ownership of the car i never bought

Hi I have a challenge with the said company. I was about to buy a car last year on 19 Dec 2018 but found that it had defects which were never mentioned. As if that was not enough the dealership registered the car in my name before i even saw the car which i warned them against. I am now facing a problem that i cant register my new car because i have to pay the disk for the other one too or else my disk won't be issued. Thats the least of my worries. I am scare now because if anything happens with or to the car in from John Williams i may be liable for for it. I meed your intervention because when i queried this they said they're waiting for the letter from bank and besides the car has been sold already. If it is sold why is ownership in my name and not changed. If ******** activities happen around the car i may be liavle for such. This is scaring me the most.And all the while i was told that i shouldn't even worry they are a Mercedes-Benz dealership therefore they cant do anything to tarnish their good name and reputation. Please help...