Manufacturing defect with Apple iMac G5

I have an Apple iMac G5 that was purchased new at an Apple retail store in Western PA. I've had this machine repaired several times by Apple at their local retail store for the same issue, freezing and blank screen on start up, but the issue has never been resolved. While still under warranty, I took the machine back in December of 2008 and they replaced the hard drive. Then in January 2009, the machine just wouldn't turn on again. I took the unit back to the Apple retail store for repair and they told me it needed a new main logic board, but the warranty had expired and it would cost me over $600 to repair it. I told them I had this machine in for repair for the exact same problem before and they never fixed it, but they refused to honor the warranty and repair the machine. I did an exhaustive search on the web for problems with iMac G5 machines and came to learn that Apple knew there was manufacturing defect with the main logic boards of Apple iMac G5 machines and that they created an Extended Repair Program in 2005 specifically to resolve the issue. According to Apples own web site, the Extended Repair Program ended on December 31,2008, well after I had it at their repair center. I went back to the Apple store with my iMac and this information in hand and they still refused to repair my machine, even though they acknowledged the manufacturing defect and Extended Repair Program. They REFUSE TO REPAIR THE COMPUTER EVEN THOUGH THEY KNOW THERE WAS A MANUFACTURING DEFECT WITH IT!! It had been in for repair several times during the warranty period and Extended Repair Program and they never replaced the logic board, never once told me about the logic board problem, and never notified ANY registered owners of the problem.