What happens when an assessment payment is late

(a) In case of default in the payment of any installment of principal and interest when due, the director of finance may within one hundred twenty days after such default commences advertise and sell the assessment unit concerning which default is made for the whole of the unpaid assessment thereon, interest and costs. The period of default shall not exceed one year before foreclosure action is initiated. The purchaser of such assessment unit shall be permitted to pay in cash the total amount of the delinquent installment or installments of principal and interest and penalty, and the balance in equal annual or monthly installments as originally provided, in which event the lien of the unpaid assessment shall remain in full force and effect until final payment of such balance. Such sale and advertisement shall be made by the director of finance in the same manner, under the same conditions and penalties and with the same effect as provided by general law for sales of real property for default in payment of property taxes. (b) In the event of the failure of the director of finance to so commence and diligently complete advertisement and sale of the assessment unit pursuant to the provisions of this section, the director of finance shall not be personally liable for such failure, but if a default exists in payment of principal or interest upon bonds, issued to represent an assessment for which any such installment of principal and interest is in default, or if the levy has been made or it appears probable that the levy will be required to be made, the holder of such bonds in the former case, and any persons who are owners of the assessment units subject to such levy and liable to pay same in the latter case, or both, shall have the right to enforce performance of the duties of the director of finance hereunder by action in the nature of mandamus, as provided by law.