So I had 6 lingots and I completed prepositions it said it gave me 2 lingots but it autualy took two away. Can you help me?
Have you tried refreshing the page? If that doesn't work, try clearing your browser cache, closing the window, and then returning. On rare occasions, you'll need to wait for between 5 and 15 minutes (and then refreshing) for Duolingo to register points, lingots, skills, and levels.
If you try those things and none of them work, will you come back and post a new comment letting us know? (If it works, also please let us know. ^_^)