Deceased Estates - Shockingly bad Customer relations.

As executor of a deceased estate, I am trying to get bank statements to file a tax return for the deceased as well as have the deceased's Nedbank account balance paid to the Estate account for distribution. Despite providing original supporting documentation, I was told it would take 8-10 weeks. That was 12 weeks ago. All mails sent to the various addresses supp**** by Nedbank are either unanswered or are returned undelivered.