FNB #item not paid NONSENSE!!!

#item paid no fund 18/12 I have never seen this on the bank charges nor i agreed to be charged for this. I cant even find the transaction that was processed where there was no funds!!. Firstly why would the transaction go through this is the First time that this has happened and in the whole process i did not even get an sms!!. A fee of R120 was deducted What nonsense is this. I need to know for what transaction was this and why has this happened now and where as before you would get a transaction declined. I want this fee reversed.