Well the trick was I bought the AT&T version of the note 4 before I bought the t-mobile one. So when I called I had my sim card in the AT&T one when I called. Lol. I have my spare note 4 in the drawer just lying around. When I called they was like, do you have a blackberry, I said no, do people actually use those anymore. Since I have my note on the next program they was like OK no problem. Then they said, is your phone for AT&T network, I said it better be because I bought it from you. Then I rebooted the phone so they could hear the AT&T boot up sound. They had me put in a new APN setting, still no LTE (on the AT&T phone at that) so they escalated the case over to someone else and changed a bunch of settings on there end. Then said maybe they had LTE issues in my area, I said nope I have a iPhone sitting next to me with full LTE. By the time I hung up, the AT&T note 4 had zero LTE and the t-mobile had full LTE, which still till this day I have no clue how that worked out. It still shows a blackberry on my account, but here was my speed earlier so it don't matter to me what the show.
Did you have a chance to test speeds in your area with both phones connected to both carriers? I am going through a dilemma right now as to which carrier I should choose to go with.