Emission Control problems of the 2002 Chrysler Concorde

Bought the car used from copper city Dodge in rome NY. Check engine light was on when test driven. Were reassured it would be good when we took delivery. After about two weeks light was back. Dealer said it was bad gas cap and fixed. About two weeks or so it was back on. Dealer said it needed to be reset, fixed. About two weeks it was back. Dealer said it was evap canister, rollover valve and an emissions valve, claimed fixed, charged us about $400. About two weeks or so it was back again. Dealer said it was a bad fuel pump would be about $700. Took car to usual family mechanic who had to replace everything dealer claimed to have replaced. Our mechanic said it all tested bad. After a month or so light was back on. Car runs ok but check engine light won't go away. This has been an ongoing problem since we've owned the car. Called Chrysler and was told we'd have to work it out with the dealer. I will not pay the dealer another red cent to fix a problem that's been there since we took delivery. I should have never paid them for repairs to begin with.