Nedbank Trust poor Executorship service

My brother and myself are beyond frustrated about the fact that our late mother’s estate has been not been finalised yet. She passed away in November 2018 and all went reasonably well until January 2021. We had two-way communication with Dorkas Sinclair who handled the estate up to then. We received a mail on 22 January 2021 stating that “We are improving our structure and processes to provide you with a better service” and Tshamano du Preez was the new contact. This is the point where everything came to a virtual standstill (apart from the Title Deed communication in March 2021). We are receiving two communications weekly from SARS about wrong banking details: one SMS and one mail per week stating that they cannot do the final refund as they do not have the correct banking details. We informed Nedbank about this in December 2020 already. After a complaint to customer service on 30 July 2021, Ms du Preez reacted on 16 August 2021 to indicate that seen that my mother had a private tax practitioner, we need to resolve it ourselves. The continuous requests for the relevant information required by SARS to change the banking detail to the estate account have been blatantly ignored – not even acknowledged. After renewed communication with customer service about the issue, Ms du Preez informed us on 11 November 2021 and 14 December 2021 to indicate that they have not had a tax refund from SARS. This I know as I receive the communication from SARS on a weekly basis. On 13 December 2021 Mr Marius Fourie from customer care indicated they (Nedbank Trust) “have committed to follow up with you once a month, the next feedback should be within the next few days.” Needless to say, after the 14 December 2021 mail, they did not contact us again. We do not know how to resolve this. It frustrates me endlessly to get these messages from SARS every weekend – a clear indication that nothing has been done to resolve it and we are not empowered to resolve it. And they do not bother to answer a mail.