Halo: MCC -- Completed all campaigns on Legendary but achievements still locked

Hey everyone, I've gone through the unlocking methods described before on the official forums such as removing and adding your account back but no luck. I have completed all campaigns on MCC. Spent all last week doing so. It shows up on my actual game screen
as all missions being completed on Legendary. However, I have not received credit for it via achievements. I'm pretty bummed about it since it's the last thing I need to complete 100% customization on Halo 5 for that Helioskrill armor Any help or am I SOL
and I need to redo the campaigns?

:)

 

HALO MCC HELP

my achievements won't pop up on mcc I've completed the campaign on easy and legendary neither will pop up there still locked what do I do

 

NOT RECEIVING MY REWARD

So my problem is that i recently completed a achievement on Halo MCC called the "legend" achievement. Basically i completed all the campaigns on Halo MCC on legendary and whats supposed to happen is a reward should be unlocked in halo 5. The reward still
hasn't unlocked yet and i completed the achievement on the 2nd of May 2018. How do i go about getting my reward? The reward im supposed to receive is the Helioskrill armor and helmet. Its really frustrating that i havent received it yet.

My gamertag is

 

I've received the same results and no armor I even finished ODST and went back to waypoint to see what I was missing finished it and still no armor