In no case shall any mistake or failure of the city clerk or the clerk's deputies or assistants to compute or collect the correct amount of any license tax or penalty prejudice or prevent the collection by the city of the full and correct amount thereof actually due. No license tax paid nor any part thereof shall be refunded or prorated; except, that any license tax, penalty or part thereof which has been erroneously assessed and collected shall be refunded by the city clerk upon approval by the city council. (Ord. 89-12 (part), 1989)