I bought a used car , with a service plan / extended warranty . Can I take it back ?

I drove this car 30 miles before it broke down ..someone put a jumpier wire in the relay box and it caught on fire..I contacted the dealer who had car towed to "his" mechanic , who in return hard wired the fans to the ignition .. an improper repair that now voids my after market warranty.. the dealer now say's we bought the vehicle as is and that he cant work with me to repair it correctly.wont give me a refund , and wont give me any paper work on repairs he authorized... Do i have any rights ? I know it's a used vehicle , but the dealer misrepresented the vehicle Quality and he had the vehicle inspected by his mechanics before he offered the extended warranty to us. This should have been noticed then , He failed to notify us of this problem and sold us the warranty in the first place. I feel uncomfortable with the reliability of this vehicle now , am I now responsible for the full amount of an improper dealer authorized repair ?