Where's my achievement?HELP!

[SoulReaver626]

a friend and i were just playing on team deathmatch (player)
I already had my achievement for 50 kills on team death match.we started a new match and i got 100 kills on him,but didnt get my achievement for 125 kills.

I already had the one for 50 kills in TDM,then got 100 kills in one game.thats 150 kills in TDM.But I got no achievement.Anyone know why?

I already restarted my system and loaded the game again,but the achievement never popped up.I'm a little upset

[Lord Rickster]

I have just done this achievement on deathmatch and it took more than the kills it states i think what it is saying is that you have to get 50 kills then 125 then 250 cause me and my mate done three matches at 100 flag and i got it and he didn't (but i have played it before online)

so keep killing him :woop:

[I King Pin 0]

To clear things up I was helping boost a friend and I boosted him up to 125 kills straight and he got the achievement so I am just hoping I won't have this problem since I stopped at 100 kills for me.