S.D. Codified Laws § 49-11-9
If, upon the final determination of litigation in which the operation of such law, order, resolution, or ordinance has been stayed, suspended, or enjoined, it is determined that the rates or charges fixed in such law, order, resolution, or ordinance are legal and valid, the Public Utilities Commission shall give notice to the common carrier, public utility, or public service corporation interested, hold a formal hearing and make and enter findings, conclusions and an order requiring the common carrier, public utility, or public service corporation immediately to make a refund persons from whom it has received charges in excess of the rates fixed in such law, order, resolution, or ordinance, and to file with the commission a sworn report, within the time fixed by the order of the commission, showing the amount of money refunded, to whom, and the date of refundment.
A violation of this section or a Public Utilities Commission order issued pursuant to this section by a common carrier, public service corporation, or other public utility subject to this title or by an officer, agent, or employee of such companies is a Class 2 misdemeanor.
SDCL 49-11-9