Interval International "steals" Christmas Vacation week

We initiated a "request first exchange" last January, 2009 for a week 51(Christmas) Marriott at Vail time share- attempting to exchange Christmas week for New Years week in Vail. Interval International deposited our week in March without our knowledge or approval. Despite many hours of pursuing II and trying to get our week back, or another equal week- we have been thwarted over and over. Interval International has accused us of incorrectly asigning the week, and accused Marriott of having multiple "request first" options. We are locked in a "we are working on this" cycle of futility and have but 6 weeks until the holidays. The week should have been returned in October and yet Interval International has done nothing to return our week or get us another comparable week or hotel room...

Who else has had a bad and/or criminal experience with Interval International? What legal options would one have in this situation? Does anyone have experience in pursuing this as a theft?