Telkom fails to bill correctly

I had an Adsl line that was paid for every month on time. I relocated to a different province and requested that my service gets cancelled. I understood that it takes 1 month notice for cancellation and therefore I logged in my cancellation on the 19th of November. The service was stopped on the 20th of December and all seemed well. Until I received an invoice(dating 12 Dec 2014 -1 Jan 2015) that billed me for the whole of the December month. I called Telkom and they reassured me that my account will be refunded. The next month I received an invoice (dating 12 Jan - 11 Feb 2015) That billed me again for a full month. My cancellation code is *** and my dispute reference number is ***1. Every call center agent assured me that they cancelled the line and that I just have to wait for my next invoice to see a refund. It never happened and every time I have to call in to enquirer about my account. This is becoming ridiculous because I want to settle my account before my credit rating takes a knock due to bad feedback from Telkom and an extreme lack of customer service.<br> <br> Please sort this out immediately because I thought Telkom was a respectful service provider.<br> <br>