FNB is ****ming people

My mom was ****med over 16000 on her fnb account, someone used it to purchase on takealot app, so her cellphone number was changed at the branch and her card was used to do the purchases that she has no knowledge of from the 31_07_2025 till the 3_08_2035 and when she realized this on the 11_08_2025 she went to the bank to lay a complaint but only today she received a letter saying they can't refund her since the bank has no knowledge of how this happened, how do we trust this bank with our money if such ******** activities are dismissed, Mayline Meyburg was the lady in charge of her case but never called, her case number is ***.