How Can i Ask A Question When No One Answers My Call?

I just have a simple question. It's not a complaint, it's not a problem, it's just a question. I only wanna know how I got a "late charge" when my account has Auto Pay? It's only 29 cents, but...how? I have no control over it. T-Mobile is 100% responsible for withdrawing the payment on the assigned date. So why am I getting penalized? I can't connect to chat, and I was on hold with customer service for 15+ minutes when I was told it would be 5.