Any notice, payment, remittance or other filing required to be made to the city pursuant to any tax ordinance shall be considered late unless it is (a) physically received by the city on or before the due date, or (b) received in an envelope or other container displaying a valid, readable U.S. Postmark dated on or before the due date, properly addressed to the city, with adequate postage prepaid. (Ord. 1904 § 5, 2001)