I am missing armor on halo 3?

[Doug H]

I have 840 achievment points from halo 3. I had the security shoulders. I went to put them on today and it said they were locked. I dont get it please help me it was my favorite armor.

My gamertag is Abo70

 

[Jim G]

bungie announced that the security shoulders are 100% glitched so there is 50% chance you keep them or not but to keep the pernament without them glitching is to get all the achievements , when i put on my securty shoulders after getting alot of acheviements i pu them on and it glitched for about 3 seconds and then they were gone i decided to get all the achievements just because i wanted to and when i did i had the security shoulders and they were pernament and now i wear them all the time