If any person fails or refuses to remit to the tax collector the tax required to be collected and paid under this chapter in the amount specified in this chapter, on or before the last day of the month in which the remittance becomes due, there shall be added to the tax by the tax collector a penalty of ten percent of the amount of the tax, and if the tax remains delinquent and unpaid thereafter for a period of thirty days, there shall be added thereto by the tax collector an additional penalty of ten percent. (Prior code § 6.12.050)