Iwant to take 2week holiday off work but they refused me?

i booked 2 weeks holiday off at the end of june however mycompany got a email back from the big guys at the top saying im not aloud that date as its the busiest time for the company which is a lie because ive been sent home earliy everyday this week and the store iwork for is rarely busy as its not in a busy area so ive tried my luck again and rebooked them for the begginin of july so they cant give me excuse about the end of the month story but ive got a funny feeling there gunna refuse them to, iknow they can refuse holidays but can they keep refuseing me surely they gotta give in and give me them sooner are later what are my rights?