Achievements not unlocking/Disconnecting from Xbox Live

I received an in game notification that I had got "For every choice an Achievement", but the achievement itself didn't unlock. Then I picked up some rent money and the in game notification said something like 10234/10000 for the "Get rich or Die trying" progress, but once again no achievement. The only thing I can think of was I was disconnected from XBL at the time, cause all of the achievements were unlocking correctly beforehand. But now everytime I get on Fable it disconnects me from XBL. Any advice?

Alright, I know the internet isn't the issue, cause I fixed the issue with it disconnecting, beat the game and got all of the achievements besides the ones mentioned above. But even when I go back to an old save, I get the notification, but no achievement. What's the deal?

I have this exact problem with the "YMCA" achievement, and the achievement you get for beating the game. I had spotty wifi at the time the achievements glitched so I know unlocking them offline was the issue. Going through a new save doesn't work, as the in-game achievement tracker still says you completed the achievement.