Personal loan complaint

Good day We have a personal loan with FNB. There was a time that we fell behind on payment, bank phoned us made arrangement, which was fullfilled. Since then the loan debit amount was stable until last month. Now without any phonecall ever we are paying our monthly installment and then by the 7th of the month they deduct another amount from our account. When we contact the bank they say it is because we are in arrears. They never phoned us after previous arrangement was fullfilled to say we are still in arrears. No phone call, no arrangement and just deducting money from bank account without any warning. I do not have any money at all to feed my family for this month.