Sorry to hear about that Jackie, what you had is called 'bud blast', which can occur due to any of several factors such as: being kept too dry, wide temperature swings, over-watering, over-fertilising, or even from shifting the position of the orchid while the buds are developing... perhaps the safest thing to do is just maintain what you were doing while the spike and buds were developing and try to keep the environment the same
I've had this happen to me too, annoying isn't it? even baby buds have dried up before they got close to bloom size. The only thing I had done was fertilize. So I decided I don't give them a drop. That worked ok, but know they need something so I have now amended that practice to fertilize, wait about 20 minutes and rinse them.. so far so good.
I fertilize the weak/weekly method.. for the above I even went weaker. So far I've not lost a bud/bloom.