Untraceable Funds

My mom has some money invested at Standard Bank, however when she wants to withdra money from any of the accounts she is given multiple excuses. She is either being told that the money is not traceable or that she is not allowed to withdraw it. She has put in claims for withdrawal but even with that the money is never released. My concern is how is it possible 1) for the bank not to be able to trace the money at all its branches 2) Why does she have to be assisted by only a specific individual 3) Why are the funds not released to her even after she has decided to close the accounts.