Conned by sales person

I bought a used Mercedes Benz B200 three months ago with the mileage of 112 000 or so, the sales person Mr Thobani Gamlashe was insisting that I should buy a warranty for R30 000 and I refused because I did not have that amount of money. Eventually the car was released to me. Now it is three months later the car has issues with the gearbox and as I write this review it has stopped running completely and am paying R4000+ including insurance. When I raised the issue with him, he shrugged me off claiming that his bosses are refusing to assist me or even check the car because I don not have warranty. At the moment I feel conned and there is absolutely no aftercare sales. I am tempted to believe the car had serious issues hence they forced me to buy the warranty.