Poor service from Standard Bank and look out they remove your authorization

About 14 years ago, my mother made a fixed investment at Standard Bank and I as her son was the authorized person on the account from the beginning. For 12 years, I instructed Standard Bank to renew the investment. When the investment expired in June 2021 they let me know I no longer have signing power and I have to take her ID to branch which I did. They tell me that investing automatically renew that I was happy with. I then received a text message this week that my mother's investment was coming to an end again. In fact, they let me know at the call center and in the Paarl branch that I do not have authorization and that my mother has to go to the bank. She is in the old age home and turns 94 this year and can barely walk. I am currently very frustrating as I have more questions than answers. How is it possible that after 12 years someone in Standard Bank decides to remove me as authorized. If I can not get my mother to bank what then. This situation can not be acceptable. I have also been a signatory on her accounts at ABSA for over 14 years now and still am. How do you just remove someone's authorized powers, especially for those who care for the elderly.