Loss of trade-in credit with Device Payoff

Dubz7

I would like to payoff my device (currently about halfway through the payment schedule) but the advertised payoff amount does not include to trade-in credit for the device I traded in. This was also confirmed by an agent when I called, stating that the credit was only valid for monthly payments. I'm trying to find where this stipulation is indicated as it is not on retail installment contract of the current device.
So essentially, if I want to payoff my phone, I traded-in my previous phone for free... Poor customer service, I'm really close to just being done with Verizon for good.

Verizon_Support

I understand checking out and wanting to understand fully how any promotional/trade-in credits are affected by paying off a device agreement. Our Device Deals FAQ has all the information related to these topics: https://www.verizon.com/support/device-deals-faqs/

If you select the ‘Deal & promo credits’ section, the first questions, ‘What kind of account changes will make my promo credits top early?’ Has the list of all items which cause that to happen, including paying a device agreement off early. Additional details over various promo credits, trade-in or discounted deals, are also to be found on this FAQ.

-John