1. If, after due investigation and hearing, any authorized rates, tolls, fares, charges, schedules, tariffs, joint rates or any regulation, measurement, practice, act or service that is subject to the approval of the Authority is complained of and is found to be unjust, unreasonable, insufficient, preferential, unjustly discriminatory or otherwise in violation of the provisions of this chapter, or if it is found that the service is inadequate, or that any reasonable service cannot be obtained, the Authority may substitute therefor such other rates, tolls, fares, charges, tariffs, schedules or regulations, measurements, practices, service or acts and make an order relating thereto as may be just and reasonable.
2. When complaint is made of more than one matter, the Authority may order separate hearings upon the several matters complained of at such times and places as it may prescribe.
3. No complaint may at any time be dismissed because of the absence of direct damage to the complainant.
4. The Authority may at any time, upon its own motion, investigate any of the matters listed in subsection 1, and, after a full hearing, by order, make such changes as may be just and reasonable, the same as if a formal complaint had been made.