Hi Barbara Jean and welcome to Orchid Board.
I would guess that if a bud has not opened after that amount of time then it's not going to. But it sounds like your care is good if the plant is growing new fans and does not have brown tips so it could just be that the bud gave up after the plant was moved from the shop/nursery to your home. That happens a lot with some orchids, not sure about these but it does sound like that's what's happened in this case.
P.S. I've moved this post to the beginner section as you will likely get more people who can answer the question there than in the introduction section. Welcome anyway