Early upgrade eligible for $200 reward?

I have gone through the process of choosing a new phone, applying my rewards code, picking the line I want to upgrade and adding insurance. On this page, the total price includes the reward, but when I go to checkout, I get the message that nothing in my cart qualifies for the code I entered. This is an early upgrade - allowed because I have made more than half of my payments. I have chatted and spoken with several reps who don’t know why I get that get the message but have various guesses and assure me I will get the reward once the old phone is returned. Can anyone confirm this? Do I have to pay off my old phone to get the reward? Thanks.