Ordered iPHONE 15 - Empty Box Arrived

I ordered an iPhone 15. It arrived in the mail today via FEDEX. The box did not look tampered with but when I opened it there was no phone but only packing paper, installation instructions, and a receipt. I messaged XFINITY support and they setup a ticket number. I having a hard time speaking to an agent. Any advice on how to escalate this to a management team that can assist with an issue like this?