I need credit on my account for line I was told I couldnt close

Hello, this is a long story that I will try to make quick. My husbands line was on my account. When his business starting expanding he moved to T-Mobile, this happened Jan 2023. A couple months later I went into my local store and said I needed cancel that line since it hadn't already been removed automatically. The guy said that was impossible for the line to be active at Xfinity and T-Mobile at the same time. I assured him that I needed to cancel the line and he said that I needed proof to show that the line is active at another provider to get it cancelled and a credit. Getting that information was a hassle. I finally went back in store to do the thing and of course no one knows what I am talking about and wont listen to me. They told me to contact support. I then called and talked to rep that said I would be credited for the whole year of service with the insurance and other add-ons, last week. However, the call was disconnected in the process of him changing my plan. The rep made no effort to contact me back. My plan was updated and I awaited the credit to my account as we discussed. Nothing was noted on my account or credited to my account. I've chatted with support who says to go in store and store says to contact support. I'm at a loss at who to reach out too. I could call again but really need to escalate at this point.