My employer has a vacation policy. I have 0ver 10 years with the company which per their plan gives me 15 days a year vacation, which is 1.25 days accrued per month. They have a limit of 22.5 days accrued time. HR just informed me that I am at my limit and will not accrue any more days until I take some of the accrued days. Is this legal to stop me from accruing more days?