Bad service and billing

Have 2 adsl line with telkom. More then 3 month ago started having problem with one... it was a 4 mb line but every time I tested I got under 2 mb. I phone telkom was told they can't cancel line over the phon, I had to go to their telkom offices. Went to their office in cape town near cape town station. Was told they can't help I must download form and complete and send it back. Did that . 30 days later. Still not disconnect. I phone was told there is nothing on system. Emailed the fax with confirmation. Few weeks later still nothing. Phoned 2 more times the same answer. Nothing on system. Emailled it again. Then telkom disconnect all my services. For none payment. I paid R1000. Then R600. Just to show that I'm will to pay but for good service. They still disconbect me. Just received a statement and they have been billing me for adsl which they disconnect. They report me for none payment. This effect my credit record. Don't get adsl from Telkom.... my adsl was disconnect more then 2 months ago but they are still billing me. ?????