The title says it all- I lost my season 2 ranked border and my honorable opponent ribbon. I did not get banned. Someone please explain?

The ribbon is easy to explain, the S2 boarder isn't.

Ribbons weren't designed to be permanent, after you get one you have to keep getting honor for the ribbon in order to keep it. Don't get honor, it goes away. If you receive a warning via Tribunal, it goes away.

The ranked boarder, I would contact Customer Service via http://support.leagueoflegends.com and have them investigate it. That is a permanent feature.