Inconsistency and disappointment

Kindly assist me with the problem given by MTM I have been treated by MTN to suspend my line for no apparent reason because I have not skipped any payment since the commencement of my contact with MTN. I then phoned MTN to try resolve this issue but the supervisor by the name off James Mohale at the call center to assist me was rude and did not give me any assistance,but he insisted on suspending my line, stating that I am on arrears that I know nothing off hence I have never skipped any payment. I then went to Newcastle MTN office whereby I was attend by Adelaide Mbatha, who tried by all means to help, up to so far there is no joy. Lately on the 29 March 2016 MTN tried to debit R1018,53 on my bank account of which MTN could not get because I have left R510,00 for MTN as it is the monthly installments. Now I'm sitting with a bank change off R115,00 as there was insufficient funds. I then went to Newcastle MTN office to enquirer about the matter, of which Adelaide Mbatha stepped in MTN return the amount of R1018,53, there after paid R510,00 as cash as per advice from Adelaide Mbatha. Now on the 25 April 2016 MTN debited R518,53 which was debited on the wrong date, as the data I signed for is the 15 of every month. Again now on the 30 April 2016 MTN debited R510,00. How can I be billed two installments in one month as I have never skipped any month? I have not instructed any personnel from MTN to change the debit data to the 25 or 30 of any month, who interferes with my my debit data data and why? Now I am being sent from pillar to post.