CMH Honda has zero integrity!

I know that car dealerships have a reputation of trying to pull the wool over potential clients' eyes but CMH Honda The Glen takes the cup for being shady as f*ck! I purchased a second hand Hyundai i20 from them in January and on the very first day that I drove the car from the dealership, the car stopped working in peak traffic! They refused to take ownership for anything but because I fought, the eventually sorted the issue out (stating that the spark plugs needed to be replaced).... little did I know that it was just a short term fix. I had the same issue over a the next few weeks following this incident and now when I've eventually decided that I had had enough, I took the car in to Hyundai service centre and was told that the car's ignition coil needs to be replaced because the current one is an aftermarket part and that's why the spark plugs need to be replaced regularly. When I raised this with Dylan (the dealer principle) he spun the story around and didn't even have his facts straight saying that the issue they sorted had to do my keys. I don't know if they took advantage of the fact that I am a woman but I will not stand for this. As promised to Dylan, I will be taking this up with the MIOSA if this is not resolved!!