The other day my firend who comleted the game signed on to my Xbox 360 to play split screen with me, and after he signed off, I was able to unlock veteran difficulty achievements by only playing one of the required missions on veteran, and at first I thought nothing about it. A few days later, after properly finishing the veteran campaign, I attempted to find all of the intel items for that achievement, Closer Analysis, and to my surprise i found my game had been 'infected' with my friend's progress, granting me his inteligence, but causing a major problem. I can't unlock the achievement now because i can't pick up any of the items trhough the campaign now, so what should i do and or who should i contact for support?