Account carrier switch T-mobile theft

I changed carriers after 15+ years with T-Mobile. I get a bill for $200 which was odd since a few weeks back I paid a bill for $200. I call to find out what's going on they say one of the phones which I didn't carry the number over was still active I tell the rep yea I cancelled the service I even told the person at the end of the call is that everything I do t need to do anything else, my accounts cancelled she said yes. Ok here I am explaining to the rep on phone just look at the account all lines are cancelled and no one's used the line your claiming he says it doesn't matter I need proof I tell him how can I have proof if over the phone if anything the looking at the activity is proof he says doesn't matter plus hes telling me tmobile is charging me for all the 360 insurance add-ons on all the lines that were cancelled the reason, the account never made changes so I'm paying insurance on phone lines that aren't even active. T-Mobile won't do anything idk what to do I feel like T-Mobile robbed me.