It shall be the duty of every seller in acting as the tax collecting medium or agent for this municipality, to collect from each purchaser for the use of this municipality, the tax hereby imposed and levied at the time of collecting the purchase price charged for its public utility service, and the amount of tax actually collected during each calendar month shall be reported by each seller to this municipality, and each seller shall remit the amount of tax shown by such report to have been collected, to this municipality on or before the last day of the second calendar month following the month in which collected, together with the name and address of any purchaser who has failed or refused to pay the tax so imposed and levied. The tax imposed and levied by this article shall apply to periodic statements rendered after July 1, 1971, for public utility service rendered subsequent to July 1, 1971, and when any such periodic statement covers public utility service rendered both before and after such date, only that portion of the charge for public utility service rendered after such date shall be such portion of the total charge as the number of days after June 30, 1971, within the period covered by such periodic statement, bear to the total number of days covered by such periodic statement. The required reports shall be in the form prescribed by the official of this municipality charged with the responsibility of collecting taxes due this municipality.