Every miscellaneous public utility governed by this act shall be required to furnish reasonably efficient and sufficient service, joint service and facilities for the use of any and all products or services rendered, furnished, supplied or produced by such miscellaneous public utility, to establish just and reasonable rates, joint rates, fares, tolls, charges and exactions and to make just and reasonable rules, classifications and regulations. Every unjust or unreasonably discriminatory or unduly preferential rule, regulation, classification, rate, joint rate, fare, toll, charge or exaction is prohibited, unlawful and void. The commission shall have the power, after notice and hearing in accordance with the provisions of the Kansas administrative procedure act, to require all miscellaneous public utilities governed by this act to establish and maintain just and reasonable joint rates when the same are reasonably necessary in order to maintain reasonably sufficient and efficient service from such miscellaneous public utilities.