I had a strange situation with my email setup this weekend. I added a 4th account, which means I have:
One IMAP account for work
2 IMAP accounts on my personal domain
One gmail account via IMAP
However, after adding that fourth account, I got some very strange behavior. My original three accounts wouldn't properly synchronize after I added the fourth one. To make matters worse, one of the accounts has disappeared from my email settings page, but is still in my applications list.
I have attempted to fix the synchronization issues by deleting and recreating the misbehaving accounts, and that seems to have worked. However, I still have the orphaned one that I can't figure out how to delete. I have hidden that application for now, but I don't think it can be good to have an orphaned application sitting around -- particularly when it has the same username/pwd as an active one.
I have a similar situation.
I had created an email account for my work email which is part of an exchange. We were then able to get BES Express set up. So I deleted that email account but noticed that there was still an entry for that in the email and calendar applications. So I deleted the two service books for that account.
It still comes back on occasion. Like if I have to re-register or activate with the BES it comes back with it - why is that???