Rates charged for services furnished by any system or combined system purchased, constructed, improved, enlarged, extended or repaired under the provisions of Sections 21-27-11 through 21-27-69 shall not be subject to supervision or regulation by any state bureau, board, commission, or other like instrumentality or agency thereof. It shall not be necessary for any municipality operating under the provisions of said sections to obtain any franchise or other permit from any state bureau, board, commission or other instrumentality thereof, in order to construct, improve, enlarge, extend or repair any system or combined system. However, billing and service disputes between the system and its customers shall be subject to review and arbitration by the Public Service Commission as provided under Section 77-3-6.