Unauthorized early debit

My account was debited earlier with FNB assuming that our company pays earlier. My current account is overdrawn and my bank is demanding that i resolve this. This is not right. An sms was sent whereby i stated i wanted a normal debit date. This is the response received when i queried. This is unacceptable. FNB will need to pay any charges. The below is assuming all companies are paid early

Kindly be advised that your loan instalment for December 2019 was released early, due to most companies paying their employees’ salaries earlier. further note that your debit order was processed once for the month of December 2019. Your normal debit order will still be processed on the 26th monthly.