69-3-402. Action to challenge commission order. (1) Any party in interest being dissatisfied with an order of the commission fixing any rate, fare, charge, classification, or joint rate or any order fixing any regulation, practice, or service may, within 30 days, commence an action in the district court of the proper county against the commission and other interested parties as defendants to vacate and set aside any such order on the ground that the rate, fare, charge, classification, or joint rate fixed in such order is unlawful or unreasonable or that any such regulation, practice, or service fixed in such order is unlawful or unreasonable.

(2) The commission and other parties defendant shall file their answer to said complaint within 20 days after the service thereof, whereupon such action shall be at issue and stand ready for hearing upon 20 days' notice to either party.

(3) All actions brought under this part shall have precedence over any civil cause of a different nature pending in such court, and the court shall always be deemed open for the hearing thereof.

(4) In all actions under this part, the burden of proof shall be upon the party attacking or resisting the order of the commission to show that the order is unlawful or unreasonable, as the case may be.