The Sales Telephone Number has Rung for 45 Minutes without Being Answered

I was moving house so a cancelled my Telkom line and ADSL. All went fine with the cancellation and in the month following, I called to ensure that the debit order had been stopped. I was told that while the line was cancelled, I had a charge on my account regarding internet usage. The customer service was very helpful in raising a dispute for the amount (as usage was impossible with a cancelled line), and the dispute has since been settled. However, I was told the the reason for this usage charge was that some additional service needed to be cancelled separately from the line cancellation, and that I should call Sales on 10213 with a TIN number: ********** , to process this cancellation. As I no longer have the Telkom line, this is not a free call for me from my cellphone, and costs me. I called and was on hold for over 10 minutes. I terminated the call and went onto the customer chat on the website. The consultant told me that the cancellation had to be handled by the Sales department and to call again as there must be a large call volume. I went into the Telkom shop and was told that I needed to call the Sales line with the TIN number. I have since called back on three separate occasions, at different times of day, and have sat on hold for over 10 minutes each time. My cell phone contract gives me 60 call minutes per month. I have used around 45 minutes calling the Telkom Sales line without ever getting through to a human being. HELP! What on earth can I do?