Marathon Achievement Glitch?

My name is [2S]Cookies!!! I am at the top with 8hrs of game play same map same sever the map was jailbreak black ops and the server had no map change on it. What went wrong i still don’t have the achievement. I worked very hard to get it.

[editline]2nd February 2014[/editline]

I really want to know anyone?

[editline]2nd February 2014[/editline]

I really want to know anyone?