8 months without receiving a device trade in credit

I am at my wits end after calling and messaging and being patient for a solution for my unprocessed trade in.

I bought the iPhone 17 in September using their promotion when upgrading to the Premium unlimited plan with a new device. The promo was for $400 plus the value of a trade in when sending it through the mail. I ordered the device and submitted my iPhone XR for a $50 estimated value at a total credit of $450. After receiving the new phone, I sent in the trade in with the provided prepaid shipping label, packaged it well, and figured that was that.

Of course, it wasn't that easy.

For weeks the device was showing as "transferring to next facility" on the USPS tracking. It was in the same town as the final destination, so I figured it was being delivered or already had and simply hadn't updated. After days turned into weeks and then months, and hearing nothing about my trade in, I started to call and message Xfinity reps to ask about the trade in progress. At first every rep told me to be patient since the trade in could take 2-3 billing cycles to post. Fine, I figured I would be fine if I was patient. Then another couple months passed and I sent an instant message to Xfinity, who assured the device would be appraised. The rep kindly credited me $30 for the wait.

A couple months pass still and I try to message again for any updates. Nothing happens and I am routinely disconnected from the reps on the chat. This is now February.

Now into April, the first rep I messaged was insanely rude and claimed that my trade in was already processed and did not qualify, and so I received no credits. I instead pick up the phone and call another rep, who profusely apologized and told me my phone WAS recevied, and would be evaluated by mid-April. Great. Almost done.

Now into mid-May, it was clear that my trade in wasn't appraised. Today called a rep who heard me out and told me to call Assurant with a provided phone number to confirm the phone was not received, and then I could call back and they would process the credit on their end. Finally. Or so I thought.

I call the number and the line is only for submitted device protection claims. Nothing about trade in devices. I can't get a hold of anyone from Assurant. Only get disconnected by the AI.

I call back later after today, and get another rep who I explain everything to. Now, this rep is telling me that they cannot credit me at all without a confirmation from Assurant, and that the previous rep who told me I would have a resolution by Xfinity even without the Assurant confirmation was a "liar" for telling me what he did just 10 minutes prior. This rep then tells me the phone is most likely lost in transit, and Xfinity is not reponsible. He claims that I would need to file a lost parcel report with USPS and seek my $450 trade in value from them. Of course this is now 8 months since i mailed the package and way past the deadline to report a lost package.

I am at a loss for words.