If any operator shall fail or refuse to collect such tax and to make, within the time provided in this chapter, any report and remittance of such tax, or any portion thereof, required by the provisions of this chapter, the Treasurer-Tax Collector shall proceed in such manner as he may deem best to obtain the facts and information on which to base his estimate of the tax due. As soon as the Treasurer-Tax Collector shall procure such facts and information as he is able to obtain upon which to base the assessment of any such tax imposed and payable by any operator who has failed or refused to collect the same and to make such report and remittance, the Treasurer-Tax Collector shall proceed to determine and assess against such operator the tax, interest, and penalties provided for by the provisions of this chapter. In the event such determination is made, the Treasurer-Tax Collector shall give notice of the amount so assessed by serving it personally or by depositing it in the United States mail, postage prepaid, addressed to the operator so assessed at his last known place of address. Such operator may, within ten (10) days after the service or mailing of such notice, make an application in writing to the Treasurer-Tax Collector for a hearing on the amount assessed. If an application by the operator for a hearing is not made within the time prescribed, the tax, interest, and penalties, if any, determined by the Treasurer-Tax Collector shall become final and conclusive and immediately due and payable. If such an application is made, the Treasurer-Tax Collector shall give not less than five (5) days’ written notice in the manner prescribed in this section to the operator to show cause at a time and place fixed in such notice why the amount specified therein should not be fixed for such tax, interest, and penalties. At such hearing the operator may appear and offer evidence why such specified tax, interest, and penalties should not be so fixed. After such hearing the Treasurer-Tax Collector shall determine the proper tax to be remitted and shall thereafter give written notice to the person in the manner prescribed in this section of such determination and the amount of such tax, interest, and penalties. The amount determined to be due shall be payable after fifteen (15) days unless an appeal is filed as provided in Section 3-7.10 of this chapter. (§ 9, Ord. 525)