i need to contact 343

[lorenzo_qp]

so i beat the master chief collection on legendary and all of my missions say they have been completed on legendary but for some reason the achievement has not appears i called Xbox support and they told me to contact 343 on this website if anyone knows a way to contact them please help me

[MopsyFlopsy]

While the domain name may confuse you at first, the official 343 site is Halo Waypoint. The forums there contain a section for support. 

 

Sometimes achievements can take a few days to unlock, but another way to check it would be to check your service record on Halo Waypoint. You'll be able to see if it has registered every mission as complete.