The court may, at any time, upon a motion stating that the terms of the assignment are not being complied with, order the debtor and trustee to appear before the court, and the court may, if the evidence justifies, or, in its discretion, declare the assignment null and void. When such action is taken by the court, a written notice shall be sent to all persons named in the assignment. The court may, on its own motion, revoke the assignment whenever it determines that the ends of justice are not being attained. When the assignment has been fully complied with, the court shall discharge the trustee and notify the employer of the debtor, if there is one, that the debtor is entitled to receive his entire salary, wages, or income directly.