Unknown debit

Morning<br> <br> Yesterday my money went missing from my FNB account. It was R1820, i didn't even get the sms to notify me when the money was taken out. i discovered that money had been taken when i went to withdraw.<br> I could view the transaction history from on-line banking last night. but this morning all my transactions have been cleared, it only show two transactions i did on Friday night.<br> I want the money returned/reversed.