raresp

you have the same email for the admin username and for the facebook account.
that’s why the facebook login linked to the admin account..

Go to your plugins folder and open file: nextend-facebook-connect/nextend-facebook-connect.php

Go to line number 352 and add #userform

Just like this:

var loginForm = $('#loginform,#userform,#registerform,#front-login-form');