Windows 8.1 Help

Access your charms menu by pressing Win + C or swipe on the right side of the screen. Press the large gear on the bottom, the press settings, and there will be a logout button.
It could be that your data isn't up to date. Go to your library in app and let the refresh process run for a little bit. If you think your data is still bad, access the settings and clear local cache.

General Help

Your Steam ID is the LAST of the URL of you steam profile.*************
Stats will be incorrect until all your games are crawled.
Send me some feedback and I'll try. Steam provides limited data.
No, I can't guarantee the game data will always be available. I don't feel it's right to do charge for something I can't guarantee.