Is T-Mobile assisting in helping customers get their batteries replaced with Apple's Battery Replacement program for the faulty iPhone 6s's?
Best answer by theartiszan
Is this the program you are referring too?
It seems to be only effecting certain phones and not all of them. Apple does not seem to be expecting this to impact all phones so they are not offering it to all devices sold.
According to this post, you will need to go through Apple directly for service on it or one of their repair service locations which is not the carriers.