Payment date

Standard bank calls me every month after the 22nd that I am in arreas.I have never changed my payment day to 22nd of every month.My month ends on the last day of the month.In month end Feb , I spoke to one of the consultants about the dates, she confirmed that she has changed my dates to last day of the month.This month of March , I still got SMS that I need to pay on 22nd and a call as well.This is really irritating and it is very bad service that they change my payday without me confirming and still cannot fix when you bring it to the bank's attention.....Please urgently sort out and stop putting my account in arrears .very very bad service always at Standard Bank.