"Collector" Achievement Help!!! (Glitched?)

[dR PowerDrain]

I eagerly started this game yesterday and began playing it with my friends steadily earning achievements all the way through act one. After I got off the game for a bit I learned my achievements were adding to my score yet not adding to my total achievements nor showing up on my achievement list. 2 recovered accounts later I was finally able to get my achievements back to normal (despite the fact that I'll need to play Act I again and reacquire all my achievements that I got before) However, there is one problem with this now. During my playing with my friends we obtained 8 collectibles and at the time I had gotten the achievement "Collector" for getting 5 at the 5th one. The problem is, the in game stats have my collectible count at 8, while the achievement is still locked for me.

I tried deleting all my saves related to the game but it is no use as it saves your progress to your gamertag I'm assuming since no matter what when I got to the start screen again it had 8/5. I've tried putting my save campaign on a flash drive and then removing it to see if it would reset but it didn't accept that either and still said 8/5. I then tried to obtain 10 collectibles in hope that 5 more would unlock it. This did not either. So why i am here is i am wondering how to get this achievement by just deleting my campaign data. Or by possibly playing with my account on another Xbox and seeing if then it works? Please, all help is very appreciated.

Edit: My problem began like it did with these guys, if that helps
http://forums.epicgames.com/threads/825280-Settings-will-not-save

[RSG Mercenary]

I'm having the same problem as well. I recovered my account onto my friend's Xbox, played through the campaign, got some collectibles, and unlocked the Collector achievement along with other campaign progression achievements. This was all done online. But when I recovered my account back at home, I lost all the achievements I had unlocked, but it still said I had 7/5 collectibles and had played the first act. I was able to replay the first act again and get those achievements, but now I have all of the collectibles and no Collector achievement. :(

[scottyman89]

i'm having a similar issue.. i have gotten the collector acheivement and the hoarder achievement yet it won't give me the pack rat achievement.. it says i have 42/20 but is still locked