Can vacation time be denied after it was already approved?

Question Details:

I had requested my vacation time in the beginning of the year and it was excepted by my old manager. I purchased my vacation package in February and now my company is saying they will not be allowing any vacations in May or in June. I am going in June and told my new manager about the problem and she said that there is nothing they can do. Can they do that? I cannot get a refund or change my package. Important Notice