Failed to Investigate Their Consultant for a ***** Case

My brother went to Carletonville Capitec for assistance with his app. A day later he was called by a person pretending to be from the bank and he told him he was at the branch to fix his app and therefore they requested the CVV number of his card to finalize everything and he never gave the person such information. The following day a simswap was done and It appears that a duplicate card was used to withdraw more than 10k from different retail stores however @Capitec is failing to assist him even to investigate obviously the consultant that was assisting him with the app does appear on their system but they are failing to investigate him. My brother has his card with him and messages from Capitec of information that was done by third parties. How can the bank let their loyal customer lose his money just like that, how will his kids go to school? What will they eat for Christmas? Have some sympathy.