Halo 3 Katana and security gone help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!?

[Andrew N]

when i was playing halo 3 i got katana and security helmet but when finish a matchmaking it disappeared i got an achievement during the match do u think that affect it so i need help getting it back because i try getting more achievement but it not working at all(the new one not the old ones) and if u can help during matchmaking or something oh yeah i can tell u how to get recon seriously i m not lying at all if u help me get achievement during online i will trade u the information on how to get recon armor not by emailing bungie