Lack of response to concerns of treatment raised

I have written to Melomed several times raising concerns about the treatment my mother received when in-patient at Melomed Gatesville. I have received automated responses, thanking me for the message but with no further follow-up. I have also written to the client service officers outlining my concerns, but have not received a response from them either. I it appears that my correspondence is being blatantly ignored. My mother was admitted to this hospital early 2022 after suffering a fall. She has subsequently passed away after a short stay in hospital. She had suffered severe dehydration, a burn on her arm from a drip and a large bedsore on her buttocks. She has also lost her voice and was sedated and had her hands tied without discussing with her family. I think it is appalling that I have not received a response from this hospital since I wrote to them in April. There is a three year window to raise concerns and the 3 years will be up by February next year. I am also concerned that the client services officers has not responded either. I am close to taking drastic measures to be heard but have tried very hard to avoid such measures. I am a nurse working in the United Kingdom but had trained and worked in Cape Town before. This whole experience is very distressing and also embarrassing to have such behaviour from such a supposedly upstanding hospital