There probably isn't anything that can be done, unless you have a contract (such as a union CBA).  Otherwise, you're employed "at will," meaning the employer doesn't need to have a reason for a layoff or firing.  So that, in turn, means they can cut your hours like this, they don't need a reason, and it's legal.You'll just have to hope some overtime opportunities come along soon.  The employer probably did this to avoid having to lay someone off.