Voice-mail and Calling topic

So I just got my moto x2 pure version which is awesome. I went to the Att store and they figured out how to give me LTE but I realized when I make a call or receive, it automatically switches to H which I think means 3G. But right after I hang up it goes back to LTE. Also I can't seem to set up voice-mail. I called my voice-mail but it says to just keep putting my 10 digit number which it doesn't recognize. Anyone have these same issues? How'd you resolve them