69-3-326. Conduct of hearing. At the hearing, both the complainant and the public utility have the right to appear by counsel or otherwise and to be fully heard. Either party is entitled to an order by the commission for the appearance of witnesses or the production of books, papers, and documents containing material testimony. Witnesses appearing upon the order of the commission are entitled to the same fees and mileage as witnesses in civil cases in the courts of the state, and the fees and mileage must be paid out of the state treasury in the same manner as other claims against the state are paid. Fees or mileage may not be allowed unless the presiding officer of the commission certifies to the correctness of the claim.