Not recieving Campaign Achievements and Co-op Issues

[Warlord0727]

I started playing the Halo 4 campaign after recieving it. I played the campaign all the way through on the Heroic difficulty while in co-op mode with one other person until we got to the Composer mission. When we started this mission we were both disconnected from the lobby and could not recconect to finish the campaign until the next day. We could also not play Multiplayer or do even Spartan Ops. We proceeded to finish that mission the next day but then the same problem happened when we got to the Midnight mission. So we waited another day until finally completing the campaign. However, neither me or my friend recieved achievements for finishing both those missions or for beating the campaign. I would like to ask for the issue to be addressed and resolved please.