Singel-Player problems.. HTMCC

Hello!
I just completed the halo 4 campaign on legendary. There where no problem until i got to the last 2 missions. I completed both of them and got over the par score limit on them as well, but i did not get any achievement nor any of the score came up on the leaderboards. Anyone know what the issue may be?
AND PLEASE DON’T SAY THAT I HAVE TO PLAY THE MISSIONS ALL OVER AGAIN

Thanks/ Adam