2002 Pontiac Grand AM wipers, windshield & visibility problems

I rented a 2003 pontiac grand am on feb. 04, 2003. It was very cold, at night, and snowing heavily. I turned on the rear defogger. It failed to clear the rear window, and I turned it on again after noticing that it had turned off. About 30 seconds later the rear window exploded; there was no projectile found. My wife, who was with me when it happened, and I believe it has to be a factory defect, and we should not be held responsible, yet we are being charged by budget, who was charged by the dealer, for the repair.

The window sash channels have broken on my 2002 pontiac grand am. This is the component that holds the window glass in place. The car barely has passed 50,000 miles and the windows will no longer stay up. The pontiac dealer will repair the piece for $150 each window.