Whenever I delete Jabber and Yahoo from my online accounts list, they reappear after a restart.

Because of this, whenever I open login, I get a large number of popups asking for my Yahoo password:

I don't mind if Yahoo! says in the list, but I really need these popups to go. Even if I type my password for each one, they open up next time I log in.
I'm using Gnome on Ubuntu 14.04. This didn't happen before in Unity, but I can't switch back to it.