Each and every seller shall keep and maintain complete records showing all purchases of public utility service within the City, which record shall show the charge made against each purchaser, the dates such public utility service was furnished, the date of payment therefor, and the amount of tax imposed under this article, and such records shall be kept for at least two years, during which period they may be inspected by the duly authorized agents of the City at reasonable times, and the duly authorized agents of the City shall have the right, power and authority to make, at the expense of the City, such transcripts thereof during such times as they may desire. (1978 Code Sec. 9-50.)