I was doing some cleanup on a topic at someone’s request, and I appear to have accidentally deleted the entire thread in a way that I cannot currently recover. My apologies, especially if you posted on that thread and your post was deleted!
As far as I can tell from searching the help forum, deleted topics/posts are actually only hidden, not deleted, and should be recoverable by admins. In fact, it seems that you can’t actually delete anything via the standard interface. The only way to do so is by directly issuing database commands on the console.