Extremely unhappy with customer service... need help!

When I moved my 4 lines from T-mobile to Xfinity, I was told I can get discounted phones. So I left T-mobile after 16 years and ordered 2 Iphone 16 plus over the phone. When my first bill came, I noticed that I was being charged the full amount (undiscounted) of the 2 Iphone 16 plus phones. I made several calls to customer service but nobody seemed to resolve the issue. I was told to just return the phones and reorder new ones. So I did! The phone were returned and confirmed received in the warehouse on December 19, 2025.  Guess what? Without my consent, my lines (associated with the returned phone) have been deactivated twice and the amount of the returned phone still charged to my account up to this day. I made several calls over several days, some lasting more than an hour but still unresolved. I'm really really really unhappy how Xfinity is not able to help me. I even went to the Rancho Cordova store, only to be told that they cannot help because my orders were made online. This is really frustrating! Right now, I still have one line that's deactivated (without my consent), and the charge of the returned phone on my bill. Can somebody please please help me!