FirstNet is either inept or scam artists!!!

On February 26, I ordered an iPhone upgrade for my wife from an iPhone 12 to a 15+ because there was a deal online. I was not able to order mine because I am a FirstNet customer and had to do so with a representative. When I tried to do a turn in, the representative said “ hey, why don’t you just pay off the rest of your phone and you’ll get a $700 credit instead of $300.” I agreed and asked if we could retroactively do the same thing to my wife’s phone because we had the exact same phone and were upgrading to the exact same phone. The representative said he could, and would cancel the current order and I could call tomorrow and request a trade in instead of a turn-in. However, he did not cancel the shipping portion and the 15+ arrived the next day. When I called customer support, they said the only way to get the deal would be to completely cancel the order send back the 15+ and call customer support when the process was finalized. The phone was returned, and although I received a notification that the phone had been returned, they had no record of it. Now that the phone was returned, online it said she owed $900 on her old iPhone 12, when she only owed about $80. The representative at that time was unable to help me on March 8, and a supervisor was unable to clarify why this was, but said she would monitor the account personally, because it was not allowing her to mark off my wife’s phone as owing the proper amount.  She stated that she would forgive the remaining amount to make things easier, and I could proceed with turning her old phone in as if it were paid off. When the new phone came, I tried following the trade in instructions, and instead of a $700 credit I was only being quoted $140. When I called customer support, I spoke with a supervisor who said this phone did not qualify for the credit, and furthermore my original phone did not even qualify for the credit! 15+ phones apparently did not qualify but a regular 15 or 15 pro would. This is the complete opposite of what all other representatives had told me. So now, my wife would just like to pay her phone off and sell it to a third-party to fetch a higher price, however the supervisor states that he’s unable to find out how much my wife owes, or how she can pay it off. I would prefer to cancel everything and go to a different company, but I’ve already turned in my old phone, and it’s been processed. At no point during any of my interactions with any of the representatives or supervisors, did I get the feeling that anybody knew what was going on despite apparently detailed notes from each interaction. I spent three hours today with a supervisor over the phone, and I am even more confused now than I was nearly a month ago when this whole ridiculous situation started. I would like nothing more than to leave FirstNet and AT&T forever, but it seems like I have to wait until my contract is over. In the meantime, I will be warning all of my colleagues in and out of the hospital to be wary of this inept and shady business.