The installment contract for perpetual care of, or purchase of a lot with perpetual care, shall provide for collection by the municipality in event of a default and such collection shall be by civil action, and the defendant therein shall pay cost of collection, together with a reasonable attorney’s fee to the municipality, and shall also pay interest at the rate of eight percent per annum upon the past due installments. All installments shall immediately become due upon the default of any of the installments; provided, however, that when perpetual care for any lot in the municipal cemetery or portion thereof has not been paid for a period of ten years, then, and in such event, the unused portion of the lot shall thereafter escheat to the municipality, and the title thereof shall revert to the municipality, which shall thereafter have the right, option, and privilege to sell and dispose of unused cemetery property, as is in this chapter provided, upon condition that the municipality shall thereafter maintain perpetually without cost of fee the portion of the lot occupied by a grave or graves prior to the date when the remaining property escheated to the municipality. (Code 1975 § 8-261(C))