Trade-In Destroyed by UPS

Hello. Some background: I mailed in two phones as a trade-in on 10/3. I dropped off the phones at UPS with a prepaid slip. I realized today that I hadn’t received notification that the trade-in was complete. I luckily kept the tracking code and I can see in the details that the package was “not recoverable and was discarded. UPS will notify the sender with the details of the damage.”

My only option is to create a claim but it says a claim has already been created. The current status of the package is “this claim requires additional documentation from the sender to complete the process”.

What recourse do I have with UPS and/or TMobile to receive the promotional value and avoid being billed for the full cost of the phones after the 30-day period ends? Any recommendations for next steps?