I took advantage of this same offer. Personally, I did not get the impression that there was any sort of "no blackout date policy". I was actually told how far in advance dates were opened up, and was told that if I wanted a weekend, I should call as soon as that date was available. I think I booked it 6 months in advance, but I had no problem finding the date I wanted. I interpreted the 60 day clause to mean that it MUST be booked more then 60 days in advance, even if rooms were available on shorter notice, not a guarantee that any rooms would be left 60 days in advanced.

It sounds like there was a miscommunication in the booking expectations. If they cannot issue a refund, I would ask if they can extend the expiration date of the package so that you have a chance to book your preferred dates.