The certification by the Clerk of the sufficiency of a referendary petition filed within ninety days after the passage of the ordinance to which such petition refers shall automatically suspend the ordinance in question pending repeal by the Council or final determination by the electors as the case may be. An ordinance adopted by the electorate through initiatory proceedings may not be amended or repealed by the Council for a period of two years, and then only by the affirmative vote of the majority of the Councilmen elect. Should two or more ordinances adopted at the same election have conflicting provisions, the one receiving the highest vote shall prevail as to those provisions.