Does anyone know how to disable SMS 2 Factor Authentication?

sparks wrote:

I have google authenticator enabled on my account, but T-mobile still allows SMS and secret questions as 2FA methods as well.  This is not secure, especially after this week's data theft.  What's the point of enabling google authenticator if it can be bypassed by selecting the DEFAULT of SMS 2FA?

I just spoke with an Agent about this yesterday.  Not a hint of a clue.  He thought this was an IOS thing, and wanted to forward me to an Apple specialist.  Very nice person, and not his fault at all, as leadership and training comes from above.  It's quite clear that T-Mobile is not offering the option to disable SMS authentication.