We have similar policy at work, that holiday balances do not carry over. This is common.
Our policy is a little flexible in a sense that, our busiest times means holiday can not be taken anyway, yet we need to take it before the end of the holiday year which runs to end of Sept for some bizarre reason. I have 10 days left myself, but cant take any until post 15 October, so they have to carry over. They cant have it both ways.
If you lose the days, you should at least be paid them.
Talk to your manager, HR, person