Terrible customer care

I have a cheque account with Standard Bank which is overdrawn by R577.19. I was not aware of the overdrawn until yesterday when I logged into the account. Normally the bank will send me a message to alert me. This morning I received a notification on my phone that Standard Bank decided on their own without my consent. Firstly, I did mot authorize for the funds to be moved, secondly I would have appreciated if someone contacted me before they transferred my money. How will I entrust them with my investments in the future if they decide what to do with my money without my consent. I am very disappointed by the terrible service. I want my money back into my account as this transaction was not authorized. This is as good as *****!!