Unauthorised debit order

I received a notification of money that came into my account,I then went into my FNB app to see if the money is there only to find out that half of the money was not there. I then called FNB to find out what happened to the rest of the money. I first spoke to this guy who couldn’t explain to me what was happening,he then cut the call on me,I called again then got through to a lady by the name of Venessa Gwala,she said to me the system is not showing what happened to the money so I should wait until 12pm.So I asked her to give me her direct line,she gave me her direct number but when I called after 12pm it was just a general enquiries number so I had to hold for another 10mins and get another consultant whom I have to explain my story again. FNB really need to account for this,it’s a lot of money. If this matter is not sorted by end of business today I’m going to the ombudsman.