Selling Cars without warrenty

I bought an Opel OPC Atra from Kia. From the begining they had to change tyres as it was smooth and brakes that was incorrect. They also had to replace the exhaust system. I had the car for one month after I bought it five months earlier. They convinced me and showed me on paper that the car still has warrenty. I asked them on numerous occasions as I wanted to be protected if something happens to the motor. Now the motor broke and Opel looked at it and said because of a litle pipe and the harness being tampered with there is no more wartenty . Kia the guys that sold me the car got fired. The current management is saying they did sell me the car with warrenty and Opel should sort it out. I have been without a car for five weeks and have to borrow a friends to get to work