(1) The commission shall have original jurisdiction over complaints as to rates or service of any utility, and upon a complaint in writing made against any utility by any person that any rate in which the complainant is directly interested is unreasonable or unjustly discriminatory, or that any regulation, measurement, practice or act affecting or relating to the service of the utility or any service in connection therewith is unreasonable, unsafe, insufficient or unjustly discriminatory, or that any service is inadequate or cannot be obtained, the commission shall proceed, with or without notice, to make such investigation as it deems necessary or convenient. The commission may also make such an investigation on its own motion. No order affecting the rates or service complained of shall be entered by the commission without a formal public hearing.
(2) The commission shall fix the time and place for each hearing held by it, and shall serve notice thereof upon the utility and the complainant not less than twenty (20) days before the time set for the hearing. The commission may dismiss any complaint without a hearing if, in its opinion, a hearing is not necessary in the public interest or for the protection of substantial rights.
(3) The complainant and the person complained of shall be entitled to be heard in person or by an attorney and to introduce evidence.