Trade-in credit problems - 5 months ongoing

I need some help. On December 19th I sent my iPhone 14 Pro in as part of a trade-in offer on an iPhone 17 Pro. I have the offer number, tracking number, and IMEI of the phone I sent in. Tracking number shows the phone was received early in January.

After waiting for the credit to appear on the bill and it never showing up, I contacted xfinity support. Overall, I've had support chats on 3/9, 4/7, 4/20, and today 5/7. I have the chat transcripts for each interaction. Each time I have simply been told to wait until the next bill and offered a small one-time credit. While the one-time credit is fine, this is getting ridiculous.

During one of the support sessions I was told to contact the Assurant team directly, which I did this morning. Assurant informed me they don't have anything to do with trade-ins and I'd have to work directly with the carrier. I had a new support session today with xfinity support after the Assurant call, and was given the same line of "wait until the next billing cycle."

I'm tired of waiting and at this point it just feels like my phone was taken with no accountability. What can I do next?

I asked for a case number on today's chat sessions and was given 186734443655759176, but I think that's just a conversation ID. I'm happy to provide any information I can to get this resolved.