UNFAIR DEBIT

I took out a contract three years ago and called to cancel several times since last year. Every time I call to cancel they say the same thing that they have cancelled it. They are always debiting from my account every month and now my banking app doesn't even give me the option to dispute the debit. I'm really tired of their incompetence. It's really tiresome to be calling them every time so that they cancel. I have had enough because I cant be calling every month for the same issue!!!