If any person fails or refuses to make any return required by this Chapter, the clerk shall proceed in such manner as he may deem best to obtain facts and information on which to base his estimate of any tax due. As soon as the clerk procures such facts and information as he is able to obtain upon which to base the assessment of the tax payable by any person who has failed or refused to make a return, he shall proceed to determine and assess against such person the tax and penalties provided for by this Chapter and shall notify such taxpayer by mail of the total amount of such tax, penalties and interest, and the total amount shall be paid within ten days from the date of such notice.

If any person fails or refuses to pay the tax required to be paid by this Chapter within the time and in the amount specified by this Chapter, the city clerk shall add to any tax due, interest at the rate of ten percent for every month or fraction thereof that the tax is unpaid. (Ord. 80-46 §12, 1980).