new phone setup

I bought a new iphone 15 pro and originally ordered it to replace a 12 mini. it came associated with the phone's number. I now want to transfer a 14 pro with a different number to it. When I tried, it now says 2 cellular plans are associated with it. I was on a chat with verizon for over 3 hours and still am but they just left without fixing it! anyone know what to do and I cannot explain how mad I am for wasting all that time!!