Dukenilnil --
Starwood Lurker posted here a few months back that room bedding reservations were guaranteed within the Starwood network. That was news to me, but others agreed.
If you're quite certain you booked a KING room and didn't receive one while on property, then I'd say you have a case with Starwood Customer Care.
Reference one of the stickys at the top of the Starwood thread page for contact info. Keep us posted.