You only have a limited time to get some intels, like the first one in 'Sins of the Fathers'. Maybe you're missing that one? Or did you use cheat codes while picking one up, because that voids the achievement?
100k 17/07/10 - 200k 02/09/11 - 300k 02/02/13 - 400k 20/11/13 - 500k 25/10/14- 600k 15/08/15
Overachiever: 58 points - 16 Staff Clubs - 8 Subscriber Clubs - C/F Clubs 15-7-3-0 - 332 XB1 club points
Winner of GSL XII and XIII, MVP of GSL XII