Trade in lost by XFINITY and won’t credit account

I sent in 2 IPhone trade ins for the free iPhone 17 pro promotion. Both lines stated the upgrade was complete but only one credited. Started this ordeal on October 14th and it’s now March 6th. Xfinity just recently changed their answers to me that they never received it and is now past the claim window for USPS which they required me to send through. What’s next in my process?