(a) There is hereby imposed and levied upon each and every purchaser of a public utility service, an excise tax upon the privilege of purchasing, using or consuming, within the corporate limits of this municipality, such public utility service.
(b) Such tax shall be in the amount of 2% of the charge, exclusive of any federal or state tax thereon imposed upon the purchaser, made by the seller against the purchaser, with respect to each public utility service, which tax in every case shall be collected by the seller and paid by the purchaser upon the amount of each periodic statement rendered such purchaser by the seller, and shall be paid by the purchaser to the seller at the time of the purchase or such charge shall become due and payable under the agreement between the purchaser and the seller.