Cancel line and still got billed

I cancel my telkom line on the 11 April 2015 at the telkom office in Greenstone mall, on the 12 July 2015 I went back to that office and my line was not cancelled. The lady cancel it and give me a printout with accounts for May, June and July that I have to pay for. The total amount for the 3 months was R900.20 then they give me kredit for R152.29 that bring the amount on R739.90 that I have to pay. I Paid it beginning of Aug 2015. Today the 22 Sep 2015, I receive a rude sms telling me to pay another R434.01 immediately or else they will suspend all my telkom services and give me over to legal actions. They still charge me rental and the account is suppose to be closed since11 April 2015. I am so tired of Telkoms way of working, telkom need people who knows what they doing to get back on track. Telkom services score a low 1 out of 10. It is bad,bad,bad.