Any such claim for taxes, if such taxes were returned to the bureau within the time required by this act, shall remain a lien upon said property until fully paid and satisfied, or until said property shall be sold as provided in this act. If a tax is not returned to the bureau within the time required by this act, its lien on the property shall be wholly lost. But where a tax has not been returned as required by this act, a taxing district may nevertheless proceed, by action in assumpsit, to recover the amount of any taxes due and owing by an owner at any time within six (6) years after the taxes first became due.
72 P.S. § 5860.312