FNB Deceased / Late Estate

My father had a will with FNB for years and we notified them after my dad has passed away before the 20th of April 2022 and they required documentation from us, we provided them with same and Rekha Chetty the estates manager of FNB Fiduciary, Wealth and Investments, has not been responding to my emails since from the 16.05.2022 and we also require explanation about information she has provided us with since we don't understand but she has not contacted us. she told us to check the values of my dads assets and I have been telling her that we can not get the value of the car because they require the letter of authority or executorship but she has not responded and she is not phoning me back, what really makes me angry is that we can not even get hold of her on the numbers provided in her email. so I really don't know because they have not started working on the matter and time is not on our side. The only thing that she is busy emphasizing is that they will renounce the matter. Why did we ask for their assistance if we did not need it? why is she busy flaunting the renouncement in our face, we would have went to a different place if we wanted other people to assist us but we didn't because we want FNB to assist us as their clients