Overdrawn account due to account not closed.

Worst experience ever , called a few months ago to have account closed , as was no longer getting a salary and to my my surprise the account is overdrawn. I fail to understand how when I made arrangements with FNB to debit on a different account and they still went ahead and kept the account open. I Called today and was taken for a ride , transferred to different departments and consultants also hanging up on me when explaining my situation. The consultants have no empathy whatsoever especially at this difficult time