Mo. Rev. Stat. § 387.030
Every corporation, person or motor carrier performing a service designated in section 387.010 shall furnish, with respect thereto, such service and facilities as shall be safe and adequate and in all respects just and reasonable. All charges made or demanded by any such corporation, person or motor carrier for the transportation of passengers or household goods or for any service rendered or to be rendered in connection therewith, as defined in section 386.020, shall be just and reasonable and not more than allowed by law or by order or decision of the division of motor carrier and railroad safety and made as authorized by this chapter. Every unjust or unreasonable charge made or demanded for any such service or transportation of passengers or household goods or in connection therewith or in excess of that allowed by law or by order or decision of the division is prohibited.
§ 387.030, RSMo