Help! New concrete patio has slabs that are lifting/heaving & cracked!?

We had a concrete patio installed in Aug.of '07 by a BBB accredited contractor that has been in business since 1941. The co. wanted to install the patio earlier than our requested date (in Sept.) due to another job. We asked again & again if the weather in Aug. would cause probs. with the curing of the patio, etc. They said no, just keep it wet. So they installed the patio the week that just happened to be the hottest that summer w/ temps above 100 & had a severe thunderstorm as they were finishing two of the slabs that are now cracked.They told us to "water it" everyday, which we did--again though this was a very hot week & they didn't cover it. Now the patio is lifting/heaving in sections & cracked on two of the slabs. The contractor came out & wants to blame it on a downspout where the water runs next to the patio & said he won't do anything unless we do the driveway too! We think it's b/c the gravel underneath wasn't compacted enough or the curing wasn't done correctly! Help!