Nedbank deducting money from account for no reason

I receive notifications on my phone when I purchase something or withdraw at an ATM, this morning I withdrew an amount and was shocked to discover that R943 was missing from my account, firstly I know that I did not withdraw it or purchase anything from the last time I used my card and secondly I got no notification from the bank to let me know that an amount would be deducted and for what reason, this is not the first time and I previously considered closing the account, which I now realise would have been a wise decision. In this day and age one would expect better service from the institution you bank with, I have quite a number of friends as well as family members who have accounts with Nedbank whom I intend to convince to move their accounts, I don't think it will take much effort as they have all been complaining as well. I opened the account in good faith and did not expect to be ****** of my hard earned money, it may seem like a small amount but what it gets down to is the principle of looking after people's money. Truly disgusted, closing my account and taking everyone I know with me.