Whenever any county or city and county in this state holds tax sale certificates which are believed by the board of county commissioners to be void for irregularity in the assessment of property or sale of a tax lien on property or otherwise, the board of county commissioners of the county or city and county may institute an action in the district court of the county, under the provisions of article 51 of title 13, C.R.S., to have the matter determined as to whether said certificates are void. Such actions shall be brought in the name of the board of county commissioners. Any number of such certificates may be included in one action, and the fee owners of record of the tax liens on the lands on account of the sale of which the certificates were issued shall be made defendants in the action. If any defendant is a nonresident of the state or cannot be found, service of summons may be had upon such defendant in accordance with the provisions of rule 4 of the Colorado rules of civil procedure. If the court, by its decree, finds and determines that any such certificate is void, then the tax lien on the real estate on account of the sale of which such certificate was issued shall be resold for taxes at the next succeeding sale for delinquent taxes; and if the irregularity on account of which such certificate was held void is in the assessment of the property, then the board of county commissioners shall direct the assessor to reassess the same, and, if the delinquent taxes are not thereafter duly paid pursuant to such reassessment, the tax lien on such property shall likewise be sold at the next delinquent tax sale following such reassessment. No appeal shall lie from the final decree of the court in cases brought under this section. No costs of the action shall be assessed against any defendant who files a disclaimer or fails to appear in the action.