Taking $500 from me b/c of not working during Spring Break. When school is closed.

​ I am an aide at an elementary school. School is closed for Spring Break. It's not possible to work. I was never told about this during my hire and they sent me this letter TEN DAYS AFTER Spring Break. I called payroll and was told there's nothing that can be done. Is there any recourse I can take? Any advice reddit?