I don't know how much help I am. Chess.com does seem buggy. I posted a diagram to a thread, and it didn't show up. After editing the post two times, it finally showed up.
Chats Disappearing

@33_blackblackblackberry, were you able to see the post to edit? Mine just seem to disappear completely. How did you know it wasn't showing up?

^^This is what the post looks like when I posted it. I posted a a diagram just now. See? It doesn't even show up.

Now,
In this post, I'm going post the exact same diagram. Then, I willclick edit and submit. Two times.
edit - And, voila!! My diagram appears, after I clicked edit and submit.
When I send a chat or reply during a game, it just disappears into the ether. I can still see chats from my opponents, but when I try to reply, it looks like it posts, and then it disappears.
I have never been rude in chat and have never gotten negative feedback or alerts, so I have no reason to believe that I caused it. Is this just a system glitch?
As a side note, I would also love to get better alerts when I receive a chat because they are easy to miss.