Section 84. Complaints as to service and price of steam heat; investigation by commission; forms of complaints

Upon the complaint  in  writing  of
  the  mayor of the city, the trustees of a village or the town board of a
  town in which a person or corporation is authorized to manufacture, sell
  or supply steam for heat or power, or upon the complaint in  writing  of
  not less than fifty customers or purchasers of such steam heat in cities
  of  the first or second class, or of not less than twenty-five in cities
  of the third class, or of not less  than  ten  elsewhere,  or  upon  the
  complaint  in  writing of the state consumer protection board, as to the
  price, pressure or efficiency of steam supplied for heat or power,  sold
  and  delivered in such municipality, the commission shall investigate as
  to the cause for such  complaint.  When  such  complaint  is  made,  the
  commission  may,  by  its  agents, examiners and inspectors, inspect the
  work, system, plant, devices, appliances and methods used by such person
  or corporation in manufacturing, transmitting and supplying such  steam,
  and  may  examine  or  cause to be examined the books and papers of such
  person or corporation pertaining to the manufacture, sale,  transmitting
  and supplying of such steam. The form and contents of complaints made as
  provided  in  this  section  shall be prescribed by the commission. Such
  complaint shall  be  signed  by  the  officers,  or  by  the  customers,
  purchasers  or subscribers making them, who must add to their signatures
  their place of residence, by street and number, if any.