i would expect frankly compensation in the neighborhood of what it would cost to take out the liner and adjust the surface, if that's what would do it..i highly doubt 1,000 would even come close, but still far cheaper than replacing. given the compensation i would be going after, i'd be trotting off to my lawyer if the guy didn't agree to do it in writing with committed dates and such. you could also for refund money back as a "bond" to ensure the work is done. that way if he did walk away from it, you would have the money to correct (if that is possible)

i know what you are saying..to some people slight out of level would be "c'est la vie", good enough. i have a garage that was out of level at the roofline by about 1.5 inches over 40 ft span from sinkage at the corner..once i noticed it, it haunted me until i got it fixed.