I accidentally deleted an admin. How can I re-ad a deleted admin? Now when I try to ad a new admin (the admin that I deleted) I receive a message telling me that the email address is already in use.
You may want to wait for a while or ask support if they can help.
Support can also activate the distinction between username and login. You will then be able to recreate a user with the same email but a slightly different login.
You may also want to vote here Deactivate user without deleting it