Standard bank unothorized debit order

Hi in the last two months an unauthorized debit orders had been taken off my account. I called Standard Bank when the 1st one happened and the charges were immediately reversed. The references were: MULTID FORAANDG ********** 25 March 202 R349.00 and MULTID FORAANDG ************ 25 April 2020 R698.00. My complaint is that it should not be possible to for anyone to be able to start debiting your account without written consent. It is a huge security risk. I get asked more than 5 questions to access my own account, but it’s easy for debit orders to go through?. When the 1st debit order went through I called Standard Bank and we reversed it at the consultant said he blocked it. A month later the exact same reference number was used and the debit order still went through. When I called they told me it wasn’t blocked. And they cannot help me block it because the amounts are not the same. So Standard Bank cannot help me and the only way is to change a Bank.