When complaint has been made to the Commission concerning any rate or charge for service performed by any telephone utility, and the Commission has found after hearing and investigation that the telephone utility has charged an unreasonable, excessive or discriminatory amount for such service, the Commission may order that the telephone utility make due reparation to the complainant therefor, with interest from the date of collection, if such reparation will not result in establishing unreasonable discrimination. No order for the payment of reparation upon the ground of unreasonableness shall be made by the Commission in any instance wherein the rate or charge in question has been authorized by law. All complaints concerning unreasonable, excessive or discriminatory charges on which reparation orders may be made shall be filed with the Commission within two years from the time the cause of action accrues. No assignment of a reparation claim shall be recognized by the Commission except assignments by operation of law as in case of death, insanity, bankruptcy, receivership or order of court.

The remedy in this section provided shall be cumulative and in addition to any other remedy in Articles 1 through 13 of this chapter provided in case of failure of a telephone utility to obey an order or decision of the Commission.