That's strange...We were there at the beginning of the month, and they offered a number. The FAQ page of Desire,
http://desire.originalresorts.com/faq.asp, even states:
"IS THERE A FAMILY FRIENDLY NUMBER THAT I CAN GIVE TO MY RELATIVES SO THAT THEY CONTACT ME DURING MY VACATION?
Yes, please send the following information to:
guestservice@desireresorts.com and we will contact you with more information and the number that can be used.
Full Names
Arrival and departure date to Desire
Hotel Confirmation Number"
I would contact them again, citing the FAQ page, unless there is something I'm missing with your original question.