Any operator aggrieved by any decision of the tax administrator with respect to the amount of such tax, interest and penalties, if any, may appeal to the council by filing a notice of appeal with the city clerk within fifteen days of the serving or mailing of the determination of tax due. The council shall fix a time and place for hearing such appeal, and the city clerk shall give notice in writing to such operator at his last known place of address. The findings of the council shall be final and conclusive and shall be served upon the appellant in the manner prescribed above for service of notice of hearing. Any amount found to be due shall be immediately due and payable upon the service of notice. (Ord. No. 669, § 10.)