Bad service

Its been well over a year that I have had my mothers estate handled by Nedbank to be told that the account is being redone due to tax reasons. Its very vague and I have now been waiting for almost 3 weeks for a return e-mail to my lawyers regarding an update with the progress. For a service which charges the maximum I'm getting little to no service from them not even a reply to my e-mails.Which are few and far between. The account sits with Michelle Williams and Ive had no response nor a breakdown of the new costs due to the apparent change in taxation? Im not happy and would like to withdraw from nedbank being the executor. I feel they are sitting with my inheritance to charge as they fit with msyelf and my sister essentially having what feels like no authority.