No explanation - missing monies from my account

On 1/1/2016 I transferred an amount of R8000 from my current account to my investment account. To date, the amount has not been credited to my investment account but has been debited from my current account. I have been to my local branch (Cresta) but, after standing in the queue for half an hour and then spending another half an hour at the enquiries terminal, I did not receive any explanation as to why this had happened or where my money was. I was told I would be phoned the next day with an explanation (which I was not) and subsequently phoned the call centre who refused to log my call or give me a reference no. but simply referred me back to the branch. When I phoned the branch, they again had no explanation as to where my money had disappeared to. Next step, to lay a ******** charge of theft against Nedbank?