FNB took money from account without client's permission

FNB just took money from, the savings pocket. That was there for safekeeping against unauthorized debit orders that run through the Business account. After I send them a mail to please cancel all debit orders from this account , still nothing happen. When I try to protect the students money for his studies' registration. FNB decide to ********ly take the money for my personal account's arrears. Since when may a bank just took money from one of your accounts to pay another. I will definitely need to change my accounts away from FNB. In one year I lost now R37 000 with FNB since they cannot help nobody to gain their money back. They even took it themselves without any consent