Tire Blowout problems of the 2004 Saturn ION

Bought 4 michelin agility touring tires (p195/60r15 87s) from sears auto on 1/15/07. On 6/26/08 rear passenger tire was flat while in the driveway. On 7/11/08 rear driver tire blew out while driving on highway. The interior side of the tire was completely ripped. On 7/16/08 front passenger tire was flat while in another driveway. Each tire showed no punctures and was not under-inflated. The defective tires as well as the 4th michelin that did not go flat yet were replaced as they went bad with firestone affinity touring s2 tires because sears didn't carry any more s class tires for the Saturn Ion. Discarded 1st flat tire. Will hold last 2 defective tires and the non-flat tire until 12/31/08. It's strange that 3 tires with no signs of punctures went flat or blew out within 3 weeks after only a 1. 5 years' use. They could have caused bad accidents. Sears dismissed my complaint since the tires were no longer on the rims. Dot hnda h5fx 4206, 4306, 4406?, and 4506.