Mo. Rev. Stat. § 379.348

Any individual, corporation, firm, partnership, association, or any similar entity or combination of the foregoing, aggrieved by any rate charged, rating plan, rating system, or underwriting rule followed or adopted by an insurer or rating organization may request the insurer or rating organization to review the manner in which the rate, plan, system, or rule has been applied with respect to insurance afforded him. Such request may be made by the authorized representative of such individual, corporation, firm, partnership, association, or any similar entity or combination of the foregoing, and shall be written. If the request is not granted within thirty days after it is made, the requestor may treat it as rejected. Any individual, corporation, firm, partnership, association, or any similar entity or combination of the foregoing, aggrieved by the action of an insurer or rating organization in refusing the review requested, or in failing or refusing to grant all or part of the relief requested, may file a written complaint and request for hearing with the director, specifying the grounds relied upon. If the director has information concerning a similar complaint he may deny the hearing. If he believes that probable cause for the complaint does not exist or that the complaint is not made in good faith he shall deny the hearing. Otherwise, and if he finds that the complaint charges a violation of section 379.017 and sections 379.316 to 379.361 and that the complainant would be aggrieved if the violation is proven, he shall proceed as provided in section 379.346.