Debit order and block transaction

I started to bank with FNB from March this year but the service that i am getting is poor, (1)i have been struggling with the debit orders that i requested them to reverse cause i already paid for them and it was around much and requested them to block that debit order but to my surprise i am still getting the debit order and i cant even reverse it from my side it is demoralizing cause now FNB is charging me banking fees which is not fair for me cause it was suppose to be sorted way back (2) I called asking FNB to block a transaction that i didn't authorize to deduct money from my account and i spoke with a guy that assisted assuring me that they will call me back to confirm the transaction and block it it was two weeks back and now each and every time when that transaction fails FNB deduct R8.50 which is a lot cause the bank deduct it every two days ,now i am looking at the banking charges that could have been avoided if they assisted me amount to R347 and i believe it is not fair to me as their client.

I am really not happy with their lack of response .