Can not get service cancelled

Good day<br> <br> I have been trying to cancel my data subscription (Home uncap prem TIN***xx) from January 2015. <br> Firstly I phoned and was informed I must submit signed and in writing that I want the service cancelled. I faxed the letter through to the required fax number. This did not work. Further I tried by email and phone again but had no success. <br> How does one cancel only part of a service from telkom? I have been paying for the unused bandwidth since January!!<br> <br> It seems the only way to get service from telkom is to first complain on helopeter! Quite frustrating! <br> <br> Best Regards<br> Martin