Money just disappeared

My money just disappeared from my account. There is no explanation whatsoever from nedbank to then everything is making sense. The was a payment of 600 that was done to my axis from standard bank account holder, before that 600 i had a balance of 444 in my account. When the 600 came through today i was surprised to see my balance was now 290. Why i called the bank to enquire, their response was to give me a statement with the purchases i did and yes those transactions already went out of my account its not like i have an overdraft that they would say it was being covered. Yes the transactions dont clear same day but that money will alredy be out of my account meaning its no longer mine. So why did they take this r800 thats the difference when i calculate and even check on my smses. Am i now being charged twice???