Phone Number - Account Information Change

If you no longer have access to your old phone number, you should use or create an authenticator (reset authenticator if necessary). If you do so, you can now choose between SMS and Authenticator as your Authentication method. Choose the Authenticator to confirm removal of the old number.

I personally used the mobile “Blizzard Authenticator” app from the “App Store” this app can also be found in “Google Play”.

When setting up the authenticator in the blizzard security section look to the app you set up for your serial number. The Serial number can be found when you open the “Menu” then open “Serial & Restore”. After applying the serial hit done in in the app, this should return you to the Authenticator page. Hit “Enter code manually” and quickly type the code into in the authentication code section before it times out and refreshes with a new code.