Ugly treatment from Telkom

I am highly upset with Telkom as I just discovered that they had been debiting money from my account on dates that I did not give consent to I have set up a debit order to pay my Telkom account on the 1st of every month and yet when I went into my bank statements I discovered that for December 2017 and January 2018 I was debited on the 30th, that was still fine but then in February they debited on the 15th and then in March up to now they've debited on random dates like the 25th the 26th the 21st and obviously if they do not debit on the day that I have agreed on knowing that there will be funds in that period of time, and they debit in the middle of the month I will not have sufficient funds. THIS is highly unsettling and not to mention frustrating because now I am receiving SMSs from Telkom telling me that I am in arrears. This would not have been the case if they had debited on the day that I have agreed upon. Due to this I am now being threatened by them to be handed over to the lawyers and yes had they let me know that they changed my debit dates it would have been a different story because if you are going to try and debit in the middle of the month you will most likely not have the full amount that you are debiting for. I hope that Telkom will be exposed for what they are doing to their customers I've been a faithful and loyal customer since last year and now I've been treated like a ********, like someone who does not want to pay. I've never been in arrears with any of my cell phone contracts. I hope the public is aware of how Telkom treats their customers.