Suspecting possible *****, they are potentially billing the same line to two businesses. They refuse to close the account!

I have run out of ideas as to how to close an account with Telkom. Yet they keep on and on billing me. I have called a couple of times and have been referred to some email address I have to send a cancellation to. Yet till this day, three months down the line they still continue to bill me. What is funny this time around is that, another company has taken over the office space I was using and now potentially Telkom is billing both of us for same service. If this is not ***** I dont know what is.