Every rating organization and every insurer which does its own rate-making shall provide reasonable means within this state, to be approved by the department, whereby any person, or persons, affected by a rate made by it may be heard on a written application to reduce such rate. If such rating organization or such insurer shall refuse to reduce such rate, the person, or persons, affected thereby may make a like application to the commissioner within 30 days after receipt of notice in writing that the application for reduction of rate has been denied by such rating organization or by such insurer. If, upon the expiration of 20 days after application for the reduction of a rate, such rating organization or such insurer fails to grant or reject the application, the person, or persons, affected may make the application to the commissioner in the same manner as if the application had been rejected by such rating organization or by such insurer. The commissioner shall fix a time and place for hearing on such application, upon not less than 10 days' notice by registered or certified mail, for the applicant and such rating organization or such insurer to be heard. The commissioner shall make such order as he shall deem just and lawful upon the evidence placed before him at such hearing.