Still no joy months later

I have been debited for almost a year now from an unknown entity and have asked the bank on numerous occasions to block the transaction as it is un-authorised. I contacted the banks representative almost two weeks ago and was told the call center would contact me. this did not happen and i made contact. I was asked to send a mail requesting the debit not to be authorised which i did and mailed it to Palesa on Friday the 27th. I just received an sms notifying me that the debit had gone off and reversed again due to insufficient funds. As per usual i am liable for the costs incurred. NOT OK!!