Any ordinance except an emergency ordinance which, in accordance with the provisions of Section 12 of this Charter, shall have gone into effect prior to the filing of a referendum petition thereon shall be subject to referendum, and further action thereunder shall be suspended from the date of the City Clerk's certification to the Council that a sufficient referendum petition has been filed. If, when submitted to a vote of the electors, any such ordinance be not approved by a majority of those voting thereon it shall be considered repealed and all rights and privileges conferred by it shall be null and void, but any such ordinance so repealed shall be deemed sufficient authority for any payments made or expense incurred in accordance therewith prior to the date of the Clerk's certification to the Council that a sufficient referendum petition has been filed.