supermedia Tried to close account 2 years ago. They keep billing for services not requested. dallas, Texas

For two years supermedia refuses to close our account and leave us alone.  we made the mistake of paying a bill they sent as they told us it was too late to cancel the printing order.  that was the wrong thing for us to do as they keep on doing it.  we did not request their ads any further and yet they keep billing.  when you call you get an outsourced third world person who seems to be helping but nothing gets resolved you just get another phone number to call and you are expected to provide written proof you don't want their services.  this even after you have already done this.