Debit order instructions not done in time

I have recently app**** for a new acc with #FNB, submitted all information for debit orders to be switched, my salary was switched but my debit orders were not done in time thus it resulted in my previous account being overdrawn and now running on a minus due to debit orders bouncing, my credit score has probably gone low as i was trying to build it nicely..im very unhappy with this situation as it has affected my financial and emotional state.. FNB must pay for unpaid items from the old account as this didn't inform me correctly.