Bad service - Trying to cancel line

I've been trying to cancel my Telkom line for months now, and still no response or action from Telkom. How can this be???? Calling the call centre is of no use, as no one answers anyway. I have send a cancellation e-mail to all parties attaching all the relevant documentation as requested on 05DEC'14, 11DEC'14 and again on 14JAN'15.....low and behold, I have just received another bill. What more must one do to cancel the line!!!