Achievement in Halo Reach not unlocking

I played through the campaign on reach and unlocked all 10 mission achievements. However once I finished the campaign I didn't receive my achievement for beating the whole campaign. I talked with service and we tried everything to get it to unlock seeing
if you guys can help.

:)

 

Achievements not unlocking

In Halo: Reach and also Battlefield 3 there are some achievements that after completing the description are not unlocking. For example, in Halo: Reach the level completion achievements are not working. I do not participate in boosting or any type of cheating.
Please help, I am serious bout gamerscore.

Thanks

 

Achievements: Done... Unlocking!

Pillar of autumn achievement not unlocking which is keeping my other achievements for completing the halo c/e on legendary arent unlocking either

 

Try the steps described in this link for a possible solution:

forums.xbox.com/.../1958241.aspx

When you reach section 3 make sure to fill the survey. After that keep playing as normally until the achievements start rolling out.

 

I tried, was on Microsoft chat for an hour trying everything including those methods, thanks though!

 

Hey there RockyTopHound,

It's likely that one of the missions was not completed successfully or in full. Did you start a mission and then stop only to resume it at a later date? If so, try to replay that mission again from start to finish and see if it pops for you.

 

I played through all 10 missions and popped all those achievements and didnt get the 25 gamerscore one to pop. I played through all 10 start to finish, and on Normal difficulty all the way through.