Make Sure that your login details are correct...when you type your password or username wrong, it says that ...instead of wrong username or password. Obviously, if you can access the account with facebook, it does exist. Make sure there is no space before your or after your username and password...happens when you copy paste.So,better to type it manually. It is quite possible password didn't change so try using old login details.

What platform are you using to login? mini client or the naruto online website (

https://naruto.oasgames.com) ?

Make sure to untick remember password for mini client and retype login details...because it could be using old saved username and password. Clear saved passwords if you are using a browser

How to check if you binded your account properly assuming correct username with no extra space or char (screenshot is from https://naruto.oasgames.com )

See what happens when I typed the wrong password

PS:I changed my password couple of time to test and it worked perfectly so far.

So go to https://naruto.oasgames.com and type the email in the create ...it doesn't say account already exists right? Most likely, account is not binded properly. Better use ingame CS(? icon) and tell them to bind your account a specific email and password...then they can check and give it to you so you can login...or the mod handling this section(Tyler). A video someone posted on binding an account to a username

https://www.youtube.com/watch?v=O8nWfMBBzYk

Also note, you can't use the same email to login to different naruto online accounts.