Irate director who was supposed to solve querry

Sometime last week when I received an SMS informing me that they will debit the money on the 17 seeing that its December and they know most people will be getting paid on the 15th, I called in to tell them that I am not getting paid on the date that they are assuming but month end so they should not change the debit date apparently the consultant I spoke to did not even bother to make notes on my account so yesterday I again receive an SMS from them claiming that I failed to pay the account, so again this morning I had to call them back and forth enquirying on what happened because I requested my pay date to remain the same, finally I get to be called by this IRATE Chris director guy who was shouting and telling me that he is not working for me when I requested something in witting to state that I won't be accumulating any intrests on my acc as their debit order bounced, he could not even answer me when I asked him what is going to happen now that I have a broken PTP on my acc, all he could do was shout and keep saying it was their system error now I want to know whose fault was that and why did they debit when I indicated that I won't have money??and why can he not give proof??!