If you have already deposited your week(s), you probably can't get them back. You cannot deposit the same week, with different exchange companies, at the same time.
Yes - you can reject any timeshare exchange that you don't want, but a much better alternative is to ONLY request the dates and resorts that you DO want.
For Hawaii, I'd use Hawaii Timeshare Exchange -
www.htse.net, as an alternative to RCI.
RCI and Interval International (II) are the two big dogs in the exchange company business - no one else comes close to their inventory.
The other small exchange companies will not have nearly the Hawaii and Aruba inventory the RCI does, because the top resorts are exclusively affiliated with RCI or Interval International, and they don't make deposits to the small exchange companies.
Timeshare travel insurance:
http://www.vacationguard.com/
Yearly coverage for all timeshare trips, instead of per-trip coverage.