Standard Bank *****ulent withdrawal of funds

R14 400 was deducted from my mother's standard bank account without authorization 3 months ago. When it happened she did not receive an OTP or SMS alerting of the transaction. The bank statement does not show where and to who the money was paid. She has been to the bank or called on a weekly basis and being told that they are still investigating. The first time she went to the bank the consultant told her she should get her money in 2 weeks time, then she was told 2 days then again that she must wait 6 weeks for them to finalize and refund her. It is now 3 months and they keep on telling her that she must call back in 5 days time and have to date not received any formal communication from them. She is 80 years old and been a customer of standard bank for more than 25 years and very disappointed with the service and the anxiety caused by the way the bank is handling this situation and not being able to explain or report to my mother who is a pensioner about funds that just disappeared out of her bank account.