Section 79 - Adequate service; just and reasonable charges; unjust discrimination and unreasonable preference1. Every steam corporation shall furnish and provide such service, instrumentalities and facilities as shall be safe and adequate and in all respects just and reasonable. All charges made or demanded by any such corporation for such service rendered or to be rendered shall be just and reasonable and not more than allowed by order of the commission. Every unjust or unreasonable charge made or demanded for such service, or in connection therewith or in excess of that allowed by law or by the commission is prohibited.2. No such corporation shall directly or indirectly by any special rate, rebate, drawback or other device or method, charge, demand, collect or receive from any person or corporation a greater or less compensation for such service rendered or to be rendered or in connection therewith, except as authorized in this chapter, than it charges, demands, collects or receives from any other person or corporation for doing a like and contemporaneous service with respect thereto under the same or substantially similar circumstances or conditions.3. No such corporation shall make or grant any undue or unreasonable preference or advantage to any person, corporation or locality, or to any particular description of service in any respect whatsoever, or subject any particular person, corporation or locality or any particular description of service to any undue or unreasonable prejudice or disadvantage in any respect whatsoever.4. Nothing in this chapter shall be taken to prohibit any such corporation from establishing a sliding scale for a fixed period for the automatic adjustment of charges for such service or any service rendered or to be rendered and the dividends to be paid to stockholders of such corporation, provided that the sliding scale shall first have been filed with and approved by the commission; but nothing in this subdivision shall operate to prevent the commission after the expiration of such fixed period from fixing proper, just and reasonable rates and charges to be made for services as authorized in this article.5.(a) Every steam corporation furnishing service may initiate a civil action to collect a civil penalty against a user of non-residential service in accordance with this subdivision. Upon a showing in such action that a user of non-residential service has knowingly accepted or received the use and benefit of such service which has been prevented from being properly registered by a meter provided therefor, the corporation may be granted a civil penalty, in addition to the value of the unpaid service, in an amount which the court in its discretion shall deem to be just and reasonable, which in no event shall be more than three times the retail value of the steam service accepted or received. In any action under this subdivision, proof that a meter has been intentionally prevented from properly registering steam service shall be prima facie proof that the user of non-residential service who accepts or receives the use and benefit of such service has done so with knowledge of the condition so existing, if the steam corporation shall first present evidence that such person took possession of the benefitted premises and used the service prior to the creation of the condition.(b) For the purposes of this subdivision, a user of non-residential service shall be a person benefitting from such service who is in possession of the premises to which the service is delivered.(c) Any civil penalty recovered pursuant to this section in excess of the actual damages sustained by the corporation shall be taken into account by the public service commission in establishing future steam rates.