All hours cut from work?

In NJ, a part-time employees' hours have been cut to 0 hours/week. Yes zero hours. Some assumptions of why it happened is 1)employer has a reputation to hire too many people and is trying to get some to quit 2)they cut their hours because the employer is paying them more than the rest of the employees, so this will keep the payroll lower. Can the employee do anything to defend themselves?