You have to call billing, I believe. Edit: nvm Can I turn the extra security of the Battle.net Authenticator on and off as I wish? Yes, you can do so through your Account Management page using the serial number on the back of the Battle.net Authenticator.
When you log in after you remove the authenticator, just leave the authenticator field empty under your login/password. It won't cause an error or anything, just bypass that process.