Standard Bank - fixed deposit gone wrong.

On 27 November 2023, I took an elderly lady that I assist, to Standard Bank, Durbanville, to inquire about her financial affairs. The bank informed us that a 12 month fixed deposit (placed mid 2023), had been cancelled 4/5 days later and the funds were then placed into a money market account. According to the bank there is no trace on the their system of who authorised this change. Numerous attempts to speak to the branch manager have failed and 15 days later we still await feedback on this inquiry. Has anyone else had this experience with Standard Bank?