Contract cancelled but still getting billed

I cancelled my Telkom subscription (landline and ADSL) on the 24th April 2015. I did this directly at the Telkom shop in Centurion. However, I'm still getting billed. I've tried on numerous to make contact with the cancellations department but simply can't get through and I don't have the time or patience to hold on for 20 minutes. Can someone please contact me regarding my account ***). Also, for over a month I did not have any internet connectivity due to upgrades that were done in the area. This was confirmed by one of the Telkom staff but unfortunately failed to get this in writing. And yet I was billed for my monthly subscription as well. I need this rectified as soon as possible