The GM is not going to help you, you need to contact Starwood Customer Service. In fact, the Sheraton is still selling room for your dates, just through
tournamentofroses.com. Check-in December 29th and out January 2nd. I think the "glitch" was that they decided to sell the hotel as a block, and forgot to pull availability off of starwood sites. That's the hotel's problem, not yours.
BTW, the package is 4 nights at $3000(couple), or $2500 (single). Check-in December 29, out on January 2nd. Includes some extras, but clearly they cancelled out your points reservation to make big $$$ another way.