Go into the option to change your password on your account. Once you have done that login with those rights you will then be able to delete the Alliance. You can then log back out and go back to choosing to login with your FB account. This is how I managed to do it anyway.
13 Oct 2016, 14:41
"It is even better to act quickly and err than to hesitate until the time of action is past." - Karl Von Clausewitz