Lost trade in phone

I mailed my 3 iPhones on 8/8/2025 with USPS using Xfinity's prepaid label. I packed all 3 phones in 1 box and used 1 of the 3 prepaid labels. On the Xfinity app,  8 months later it still shows in transit. I've been calling Xfinity each month, placed on hold for hours, in fact a week ago I was placed on hold and waited for 3 hours and nobody answered. The USPS tracking is no longer valid, and I am not getting any help from Xfinity. I've tried to make a claim for a lost phone on Assurant's website, and to my surprise when I typed the IMEI number, all my 3 IMEIs are allocated to 3 different phone numbers. It only shows the last 4 numbers, and asking to send a text to those numbers to provide a PIN in order to file a claim. That proves that  Assurant received my phones and were re-sold in the secondary market. Why XFINITY cannot track the IMEI numbers and put a stop to my ordeal? I filed a complaint with BBC and I was contacted by Xfinity, I received credit for 1 phone, but because I only used 1 prepaid label, Xfinity doesn't want to honor the credits for 2 of the phones, even though I have proof that my packages weighted 1 lbs and 9 oz, which is the estimated weight of 3 iPhones 15. Anyone else have a similar case? It's been the worst experience ever. I've  traded in phones with TMobile and they took my trade in phones in the store.

@Xfinity Support  why do you put the burden on the customers and not help out? Customers are not liable after they dropped the package at USPS. 

Any advise how to get Xfinity to honor the credits?