I've been having issues with my iPhone 6. While talking on the phone the call gets breaken up. Either they can't hear me and I can't hear them or they can't hear me but I can hear them. Or I will randomly get the call fail message. It happens too frequently to be some kind of glitch. I called Apple they said it is not the phone. I have AT&T and never have had an issue. I've also read someone having a similar issue and mentioned something about wifi calling/lte (not sure what they meant by that). Has anyone been having this same issue?