Need help changing account name and pass

I want to change my account name and pass. But when i go to the anet site and it asks me to enter account name and pass my account name doesnt fit.
WHAT DO I DO?

By "account name" do you want to make the name the same as one of your characters? Or do you want to change your email address?

To change account name to one of your character's name, you have to talk to Tolkano, in your Guild Hall.
To change your email address, you log into the game once, and click Edit Account which is on the bottom left of the screen. Click "Change Email Address" and a screen that requires you to type your password, current email address, and new address.

To change your password, you goto the same "Edit Account" screen, and click "Change Password".

i click "change email address" and it brings me to this site
https://secure.plaync.com/cgi-bin/plaync_login.pl
it says existing customer and asks to enter account and password
my email address doest fit in the account slot
?
Edit: My account name that you can change at Tolkano doesn't fit either
?

if you are being sent to the Nsoft site you visited the store and automatically linked your EX login name to the new master NCsoft account.

use the login name and password you used then as your original email login has been changed into just that...........a login name with the master account being where you change CONTACT email and GW login password