The city council may at any time for good cause revoke, cancel or suspend any and all licenses issued pursuant to the ordinance codified herein upon a hearing held not less than three days after written notice of the time and place thereof has been served personally upon the licensee or the licensee’s duly authorized agent or manager, or by depositing the notice in the United States mail in a sealed envelope, with first class postage prepaid, addressed to the licensee or his duly authorized agent at the last known address of the licensee or agent, respectively, if such licensee or agent cannot be found in the city; and in such case no part of the unearned portion of such license fee shall be refunded.