Why was my trade-in rejected?

Hello,

Last December, I called Xfinity on a billing issue that was solved quickly. Then the agent 'nicely' offered me a trade-in saying for X'mas gift. In the past, I always buy new iPhones from Apple directly because I need an unlocked phone for travel. I asked her whether the phone would be unlocked or not. Her answer was no worry. So I agreed to trade in my iPhone 14 PRO in like new condition for an iPhone 16 PRO. I sent the phone within 7 days after receiving the new phone. Then I realized the new iPhone was locked. I called Xfinity and I told them I needed an unlocked phone and if the phone can't be unlocked, I wanted to cancel the trade-in. But they didn't want to cancel the trade-in. Talking to Xfinity several times over several hours I got the information on the phone being unlocked in a week and a promise the phone could be unlocked after a month and finally I realized all were false information or disinformation. Finally, I held onto a supervisor and she agreed that the phone would be unlocked after I paid off the phone and the trade-in credit would continue to be paid to me each month for 24 months. She said this would keep me as an Xfinity customer for 24 months. I thought that was fine since I was exhausted in this trade-in. 

A month later, I got an email that Xfinity rejected my trade-in claiming the mismatched IMEI, which was wrong. Then I called Xfinity and the agent said the issue was on the Xfinity system the IMEI was wrong in the system and he fixed it. But A few days later, my trade-in phone was returned to me. Since then I asked Xfinity to fix the issue by sending me the shipping label so the trade-in could continue. I called Xfinity many times and I was told the shipping label would be sent to me in a day, later I was told I could use the previous shipping label to send the phone back. I checked using a used shipping label wouldn't work. So I called Xfinity several times for a new shipping label and I went to the Xfinity store. It seems that they couldn't create the shipping label. 

Tell me when Xfinity can send me the new shipping label to continue the trade-in. Or you can take the iPhone 16 PRO back and refund me fully. I never want a lock phone but was tricked to get one. 

Here is the escalation ticket number, [Edited: "Personal Information"] which was created 3 weeks ago. If you can't send me the trade-in shipping label, you need to allow me to return the phone Xfinity sold me since Xfinity rejected the trade-in with a bogus reason. 

Regards,
[Edited: "Personal Information"]