***** within Standard Bank?

A ***** was committed to my bank account in the morning. I reported it immediately to SAPS, and got a number. Then by 15:00hrs that same day I communicated the loss to Standard Bank. They claim that they are totally at a loss to establish where the money was transferred to. Now my understanding is that at some time each night, maybe after 21:00hrs, all the inter bank transfers occur. Thus by my reasoning they should have been able to locate and prevent the transfer of those funds out of my account, All Standard bank did at the time was offer to refund 50% of my loss. I accepted the 50%. Now the bank is claiming that I accepted that payment as a Full and Final settlement. That I did not do - I accepted it as an interim refund of my money, pending further investigation by their ***** department. Now I have been requesting updates regularly, some requests have been completely ignored, or the contact person is away on leave, and all that I am offered is some feeble excuse. Remembering, that the ***** was perpetrated at about 09:00 hrs, and at 13:00 hrs I had reported it to SAPS, and by 15:00 hrs, I had made you aware of the loss. Now according to my understanding, all transfer of funds from one account into another, happens after 21:00 hrs that night. With that established, why was Standard Bank NOT able to intercept that *****, and prevent the loss of funds. Perhaps I should seriously consider changing Banks, unless they wisen up and refund the balance owing to me.