Wrong Phone Number on Account

I brought over a phone from Verizon (BYOD) for a 3rd phone on my plan. We activated the phone but after a few months I noticed the data was high. When I downloaded the app I recognized that the wrong phone number was associated with my account. It was a number I had never seen before and when I called the person spoke Spanish and said they were in Mexico (I am not getting roaming charges). Up until a few days ago the phone I brought over was working so basically the incorrect number was on my account and the intended number was on someone else’s account. I can not get anywhere in store or over the phone to get resolved. At this point it’s been 10+ hours to try and fix and no one can figure this out. HELP! I will leave Xfinity if someone can’t figure out the basic question of why I have paid over 6 months for a phone on my plan that I have never seen.