The department shall not finally refuse to approve a plan submitted by a political subdivision under section 8, and shall not terminate an approved plan, without reasonable notice and opportunity for hearing to the political subdivision affected thereby. The findings of fact made by the department acting within its power shall, in the absence of fraud, be conclusive, but the Michigan supreme court shall have power to review all questions of law involved in any such proceedings of the department: Provided, That application for such review be made by the aggrieved political subdivision within such time after a final determination by the department, as may be prescribed by statute or rule of said court.