Iphone 15 Stolen in transit. Xfinity rejected my claim even with police report and pictures.

I ordered an IPhone 15 and new line with Xfinity on January 8th. I already have 5 other lines with Xfinity and have been satisfied with their service. When the box arrived it was taped and looked normal so I signed for it. I took it upstairs and opened the box and found someone between Xfinity and my house had had stolen the phone only from the inner apple box and taped everything back so I wouldn't notice. I called Xfinity within 5 minutes of receiving the package. They told me they would open a case and I needed to take pictures and open a police report. I did both that day. After a few days, with no explanation, they closed my case. I called again and opened a 2nd case and then also took the box and the police report to an Xfinity store to have them add the info to my case. Xfinity also emailed me so I also send them a digital copy of pictures of the retaped box and the police report. They sent me a text informing me they were working on it and that there was no need to contact them. Today I received a text telling me the case was closed and an email that I'm posting here rejecting my claim without explaining why or how I might appeal this decision. I sent customer service everything they asked for and did it immediately. I'm very disappointed with this level of service. Xfinity has been giving me the runaround for 3 weeks now and I'm seriously considering finding a new cell phone provider as I'm now paying hundreds of dollars for a phone I never received. 

Any leads on where I can go next?

Your claim request for the following shipment has been denied:  

Claim Reason: Missing Contents
XM Case: [Edited: "Personal Information"]
Ship Date: 2024-01-08
Order ID: [Edited: "Personal Information"]

If you are enrolled in the Xfinity Mobile Protection Plan (XMPP), you may contact Assurant to request a replacement device at https://fastclaim.com/xfinitymobile or by calling (855) 884-9771.

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Xfinity Mobile
1701 John F. Kennedy Blvd.
Philadelphia, PA 19103
www.xfinitymobile.com