Microsoft Xbox Live Promotion Scam Internet

I renewed my XBox Live Gold membership last February after Microsoft announced a promotion to provide a free game with the renewal.  It stated an email would be sent and I received it in a day or two.  I completed the process described in the email and was told the game would arrive in 8 to 10 weeks.  By July we had still not received the game and we contacted XBox Live Support.  They indicated there had been a mix up but they would correct it and we would receive the game but it would be an additional 8 to 10 weeks.  Shortly thereafter we received a phone call confirming that we were good to go.  Now in October, we still have not received anything from Microsoft or anybody else.  I contacted them again yesterday and was told that the agreement I stated that it was "while supplies last" and, because of their mistakes, supplies ran out before my order was filled.  End of story.  No substitute game, no refund, no free subscription time ... nothing.  I contacted the credit card company to see if I could dispute the charge that way but too much time had passed.  I expected more from a seemingly reputable company than infommercial rip-offs but I have found similar stories online about Microsoft with other promotions.  I was wondering how they manage to retain any customers and have decided that, if I have anything to do with it, they won't.