(a) All charges made for any service rendered or to be rendered by any common carrier by motor vehicle engaged in the transportation of passengers or property as provided in § 23-13-236, or in connection therewith, shall be just and reasonable. Every unjust and unreasonable charge for such a service or any part thereof is prohibited and declared to be unlawful.
(b) It shall be unlawful for any common carrier by motor vehicle to make, give, or cause any undue or unreasonable preference or advantage to any particular person, port, gateway, locality, region, district, territory, or description of traffic, in any respect whatsoever or to subject any particular person, gateway, locality, region, district, territory, or description of traffic to any unjust discrimination or any undue or unreasonable prejudice or disadvantage in any respect whatsoever.
(c) This shall not be construed to apply to discrimination, prejudices, or disadvantages to the traffic of any other carrier of whatever description.