T-Mobile billing Problem

I had a major billing problem. My bill is normally $92. This month I got a bill for over $800. Last month T-Mobile had charged someone else's use to my bill, but supposedly fixed it. So, now they've cancelled my phone service. I can't see any of the activity for my phone service on my.tmobile. When I call, I now longer have an account with T-Mobile. Help! Is there anyone at T-Mobile that will listen?