Trade in phone offer a disaster

I am an Xfinity customer and my entire family is on my plan. I recently purchased a new cell phone for my son who is away at college. While purchasing the new phone, I decided to do the trade in offer for his old phone. I was told I would receive a shipping label to send the old phone to Assurant and it must be received by them by a certain date.  I received the new phone pretty quickly.  I also received an email from Xfinity instructing me to send my trade in phone to Assurant by October 1, however, the link in the email for the shipping label was broken and no shipping label would load no matter what I tried.  I attempted to resolve this online, but just went in circles. There is no customer service online. I then tried calling. I was on the phone with an Xfinity representative, who at one point, told me the solution was to "reset my wifi connection" to see if the link would repair. Because I was on the Comcast/Xfinity landline, I immediately lost the call connection while doing this (which I should have declined to do). On 9/21/25 in desperation, I went to the local Xfinity store, who helped me by setting up a ticket for this. They informed me I had received an RMA and not a shipping label in that email, and should be resolved in a few days.   I received an email on Tuesday 9/23/25 saying my ticket had been resolved (no details how it was resolved) and I would be receiving another email shortly. It is now Friday 9/26/25 and I have received no further emails. It will be impossible for me to get my old phone to Assurant by 10/1/2025 so I will now be out of the trade in amount which I took into account when purchasing the new phone.   I have emailed the agent at the Xfinity store for assistance but have not heard back. I feel that Xfinity is doing some very deceptive business practices by not having a live human to assist and also deceptive about the trade in process.