FNB Not debiting Loan repayments on time to get their clients account to be in erreas

I have a personal loan with FNB when they see progress of the loan settlement they dont debit the amount agreed upon on the date they are supposed to debited so that the loan can be in erreas . I spoke to a very untrained and uprofessional consultant by the name of Mpho , she told me that the agreement i signed stipulated that theres a payment break for all FNB clients . I then asked her to send me the agreement which she claimed i signed , after sending she went quiet on the phone for 10 minutes and then hang up the phone. THIS IS HIGHLY APPRECIATED AND INCONVINIENCING