Cannot get someone to fix the account

MFC Incorrectly debited my account for which they apologised. I reversed the debit immediately and it shows on my account as reversed, but the funds do not show. It is like 1 + 1 = 1 on the statement. Should we be concerned with the logic of their on-line banking system? I reported the issue on their website and duly received a report stating that they would attend within 24 hours. This has not happened. I called the call centre and sat on the phone for over a half an hour being put through from one dept. to another. Finally I have given up and resorted to hello Peter. I need the money to show in my account please.