(a) A gas utility may not directly or indirectly charge, demand, collect, or receive from a person a greater or lesser compensation for a service provided or to be provided by the utility than the compensation prescribed by the applicable schedule of rates filed under Section 102.151.
(b) A person may not knowingly receive or accept a service from a gas utility for a compensation greater or less than the compensation prescribed by the schedules. A rate charged and collected by a gas utility on September 1, 1983, may be continued until schedules are filed.
(c) After notice and hearing, the railroad commission may, in the public interest, order a gas utility to refund with interest compensation received in violation of this section.
(d) This subtitle does not prevent a cooperative corporation from returning to its members net earnings resulting from its operations in proportion to the members' purchases from or through the corporation.