Deleted user but username shows is already taken

As i want to test out the send email feature for newly created user.
I used the admin panel to delete a previously created user with contents.
The user is then became blocked user.
In the blocked user, i clicked on the “Delete user with contents” again and the user still remain in the panel of blocked user.
Then i went into command prompt as follow
sudo gitlab-rails console
user = Users.find_by(username : “user1”)

return the user id
1 (this means the record has been deleted)
However, i tried to register for “user1”, the webpage will say that “user1” has been taken.

As i restrict user sign up based on email hence i need to reuse the either the username or email address. Please advice