Apple Music subscription included from Verizon but telling me my Apple ID is already in use on another device which is not true

I have an Apple Music subscription through Verizon wireless when I use the link they give me that shows it’s included through my cellular provider it tries to sign me in and every time comes back that my Apple ID is already in use on another device. It’s not though my daughter has her own Apple ID and is signed in on her device under her own Apple ID and her Apple Music from Verizon works fine! I have spent hours with Verizon trying to fix it and them opening work order tickets for me but it’s NEVER been fixed it has to be an issue I need to fix through Apple and when I go in my settings on my I phone it lets me turn sync on but it shuts off immediately right after telling me to enable it and turn it on

PLEASE PLEASE HELP