FNB allowing unauthorised debit orders

For two months in a row i have have unauthorized debit orders on my account. (1. Mzansi4more 2. Value added rewards.) I have not heard off either of these companies yet the both registered debit orders on my account without my approval. When i contacted FNB they told me to contact the company myself. This bothers me as I expect my bank to due a degree of due diligence before loading creditors to my account. What is worse i s that you get charged a reversal fee for each stopped or disputed debit order. On both occasions i was sent an sms notifying me that the said company had loaded a debit order to my account. when i notified FNB that this had happened they stated that they cannot undo anything as the money had not been taken from my account as yet. I am highly disgruntled as these two occasions are not isolated ( only recent months July and August) as this has happened earlier this year and last year.