Vacation packages booked with travel agents need to be paid off 45 days in advance. If you decide to cancel, most places will refund 100% of deposit if cancelled outside of 45 days.
I personally know someone who probably will not go, but is holding onto the ressie (for resort, not dining) just in case. I would keep trying, especially inside the 45 day window. Some may cancel.
Also, at CRT, you can cancel up to 48 hours before you are charged. Try calling while you are there too. Just in case, have a back up.
Good Luck!