Xfinity will not credit my account for a phone returned

Placed an order for the iPhone 17 pro max on 1/29/26. Shipped it back on 2/4/26  and chatted on 2/10/26 that the shipping was delivered on transit. 3/19/26 receive an email that the phone was not received. Have been trying to get customer service to look up the tracking number that I no longer have and track the package. On 3/21/26 shift manager Chris said that they have the phone and he sent it to the higher ups to credit the account which I have the call recording of him saying this. On 3/22 they said the ticked was resolved in my favor the tracking number shows that I didn’t send the phone back and it was not received by the vendor you use. I have sent this phone back and I want the charge for this phone taken off or the phone returned to me.