Lost trade in iPhone

I sent back a iPhone 15pro for device credits trade in. I sent back phone on September 22 and the package with usps says delayed but it’s been at the same location for a week. I called Xfinity about the device credits and they said there nothing they can do till the receive the phone and contact the carrier. So I called usps and they said the package may be lost but still a chance it may get delivered but most likely not. So frustrating this is not my fault and now I Xfinity is not helping resolve the issue. Please help!!!