Confusion over POA

My sister called standard bank home loan on 21 Jan 2020 to find out what the settlement amount is on her home loan she was told they couldnt assist her because she does not have power of attorney on my mothers account the person who is loaded is me and that I should call in to get the information im looking for. I called standard bank home loan the consultant confirmed i was loaded on the system as having power of attorney but he couldnt tell me what the settlement amount is because the account is in arreas. He said he would speak to another consultant who will be able to assist me with the information he then transferred me to Alta Van Wyk (manager Thembeka Khoza) who told me she cannot give me any information because i am not loaded on the system as having power of attorney and i would have to send her a copy of the power of attorney. My question is how do i go from having power of attorney and passing all the verification questions then a few minutes later i no longer have power of attorney and i should email a copy of the power of attorney which the other consultant had? This power of attornet was done more than ten years ago how am i expected to send a copy of the power of attorney which some people seem to have in their system and some dont? How was i able to pass the verification checks if im npt loaded on the system as having power of attorney? Unfortunately this is not the first time this has happened the very first POA that i did many years ago Standard Bank lost it and i was told i had to do another one now some say I have it and some say I dont which is which? This is the reason i left standard bank many years ago and never looked back.