Xfinity rep did not add insurance to my new iPhone which I lost and NO ONE will help me

I have been with Xfinity mobile since 2023. Every phone I've had with them I've paid for Xfinity Mobile Care. On December 12, 2025, I upgraded to the iPhone 17 Pro Max and gave my son my iPhone 16. The sales rep was supposed to keep the insurance on the iPhone 16 and add insurance to the new iPhone 17.  I lost my iPhone 17 on December 26, 2025. I put in a claim with Assurant and was denied because they said I was not covered.  I went back to the sales rep and asked him if my phone was insured. Before he looked at my account, he answered me with confidence and said, "Of course." He then looked at my account and turned white as a ghost. He said he didn't know what happened and asked me to come back the next day after he spoke with his manager. I came back the next day and he told me that he found a way to possible get Assurant to reconsider my claim. He said he was going to tell them that there was a glitch in their computer system and that I did have coverage. This was not true. This was how he intended to handle his mistake. It didn't work. He and his manager Ernie were supposed to find a loophole to get my phone replaced but after numerous calls and texts, nothing was done. After a month of trying to get this resolved, Ernie said he was passing it to his manager but I had to wait for a response because his manager had a death in the family. I called Xfinity this past Friday and a rep escalated my ticket. I just found out that I was denied again and was told there was nothing Xfinity could do as I needed to have this resolved with the retail manager Ernie. I am paying Xfinity for a phone that I do not have. I'm not paying Ernie. I don't understand why Xfinity won't intervene and help me out. I've never missed a payment and have been a good customer. Does anyone know what I should do about this?  Has anyone filed a complaint against Xfinity and have it work out for them?