HELLO EVERYONE. KELWIN WRIGHT TALKING...
IF YOU HAVE PROBLEM WITH CREATING NEW USERNAME FOR YOUR FACEBOOK PROBLEM HERE IS A SOLUTION :
1. YOU NEED NEW FACEBOOK ACCOUNT OR TRUSTED FRIEND
2. GO TO YOUR FACEBOOK PAGE>SETTINGS>PAGE ROLES>ADD YOUR NEW ACCOUNT OR FRIEND AS ADMIN
IF YOU HAVE PROBLEM WITH CREATING NEW USERNAME FOR YOUR FACEBOOK PROBLEM HERE IS A SOLUTION :
1. YOU NEED NEW FACEBOOK ACCOUNT OR TRUSTED FRIEND
2. GO TO YOUR FACEBOOK PAGE>SETTINGS>PAGE ROLES>ADD YOUR NEW ACCOUNT OR FRIEND AS ADMIN
Alright now your problem fixed. Now you can set username to your with your friends account or new account.