Lack of response - as usual

I made a mistake with the account number when paying one of our telephone accounts in October 2015. I wrote to Telkom at the time, explaining the error and asking them to reallocate the funds from a redundant account to the correct account. Since them I have addressed 4 mails and countless telephone calls to them and as yet have received not a single response. When I phone I hold on for ages listening to their recording about how many calls they have (which I am sure they could have resolved between 2009 and now if they cared to) and eventually the line goes dead. The interest is mounting up and I am getting more irritated by the month.