Same happened. I booked a Dubai tour in March, before I booked, EXL said they only needed 4 more. So the four of us joined. A day before deadline when they should confirm "go" or not, I asked them, they still said they needed 4 more. Eventually they cancelled the tour. And they always have the right to cancel provided that they gave the customers 7 days notice. And they could cancel the tour for whatever the reasons: insufficient no. of ppl, the hotel was full blah blah...
So what I usually do is to prepare a back-up plan always (mostly self travel package) just in case the operator cancel the tour. Furthermore, 2 years ago, I called in , less than 7 days prior to my travel start day, to different tour operators and asked which tour definitely would "go" within that period, and picked the one that I liked the most. Finally we had our holidays in Beijing and stayed at Ritz Carlton at only HKD2388. What a good bargain, no need to hectic.