39 Miss. Code. R. 1-15-102
The Commission may, at any time, on its own motion or the motion of the Staff make investigation and order hearings into any act or thing done or omitted to be done by any public utility, which the Commission may believe is in violation of any provision of law or any order or rule of the Commission. It may also through its own experts or employees, or otherwise, obtain and introduce such evidence as it may consider necessary or desirable in any formal proceeding in addition to the evidence presented by other parties. Orders and pleadings initiating investigations shall specify the matters to be investigated, and shall be served upon the person being investigated.
The Commission, either upon its own motion or upon receipt of written complaint, may at any time after appropriate notice has been given, summon any person within the Commission's jurisdiction to appear in a public hearing and show cause why such person should not be compelled to comply with any applicable statute, rule, regulation, or order with which the person is allegedly not in compliance.
In any case in which an investigation has been instituted herein or where formal complaint has been filed and an allegation is made that a utility or other person is threatening to discontinue a customer's service, the Commission may, after notice and opportunity for hearing, issue an order requiring the utility or other person to continue to provide service during the processing of the complaint. The Commission may issue such an order for good cause, on such terms as may be reasonable to preserve the rights of the parties during the processing of the complaint.
39 Miss. Code. R. 1-15-102