Hey there Brythal,
Thanks for your patience while we investigated this issue for you. I reviewed the case we have for this, and it looks like you may not have noticed or received our message about this.
About a month ago we heard back from the developers on your issue - and it appears that your issue is a very rare situation. From what we can tell, it’s likely due to being in too many communities. Because of the way the communities system works, there is an upper limit to the number you can be in on a single battle.net. This includes all guilds, all in game communities, and all battle.net communities. Most people don’t come anywhere close to this limit, but you have 5 accounts with over 100 characters between them on this one email.
You should leave as many communities as possible across your characters to resolve this issue. I suggest starting with inactive guilds, or leaving communities you seldom use on characters that you do not play often. This should allow you to backfill your community slots with your new characters which you play more frequently.