The hosting move is likely the cause, though I'm surprised you're having issues if it happened last week. It sounds to me like there are delays in DNS being changed, which means some people are still accessing the old server and some are accessing the new server. You may be receiving an email from someone replying to an old server but when you access it yourself, you access the new server so can't see the post. This should work itself out if that's the cause, though normally it'd sort itself out in 24 hours or so.
Unfortunately, I am just guessing a bit. While I can see your forum, as a guest, I can't see anything. If you wanted us to see the content, we'd need you to provide an account we can login with (you could do this via a ticket in your customer area).