Good evening everyone,
I'm sorry for the ongoing problems, we're going to do all we can to get everybody up and running again as quickly as possible. I've updated the first post in this thread and have now locked the thread accordingly.
We're reaching out to everybody who's responded to say the 'mailbox unavailable' error is still present, you should get a PM from our ModTeam soon. If anybody is reading this post with the same issue, please refer to the first post in the thread and create a new post. Our staff will be in touch within 24 hours to get things working again for you.