Phone trade in lost in transit

I upgraded from an apple 15 pro to Samsung phone. I sent my apple 15 pro in for bill credits with the supplied shipping label on December 22 2025 and have the tracking number for it. According to usps as of February 18 2026 it still says stuck in transit. I did a lost mail search with usps on February 2 2026 as requested from Xfinity customer service. Package is still missing. I call Xfinity customer service 6 separate times and they keep sending me in circles. I contacted customer service via the app and documented it with screenshots and a copy of the transcript. The online agent in beginning of February said “not to worry package will be delivered in 24-48 hours” but it is still missing. My phone bill is going up next month over $300 for one month which I can’t afford all because that is what was left on device payment. I got the phone for free for joining Xfinity a year and a half ago. I don’t understand why I have to pay for a phone I got for free and was lost via usps the only option I had to send my old phone in to do an upgrade. I’ve had a lot of cellular carriers in the past I’m extremely happy with the service I get on my cell phone but I’m extremely unhappy with the customer service provided on something that was out of my control since usps was my only choice in sending in my phone trade in.