R.F.
Could you use that "confidential" letter and its manner of execution to your advantage?
Could you not send your own letter (without appearance) to the BOE to tell them this elder is a troublemaker and spreading gossip about you through delivering "confidential" letters without courtesy of sealed envelope and distributing them to your family in order to purposely cause disharmony in your life?
Surely you can find some scripture for his chastisement. Use his manipulating beligerence to cause him some reproof.
Perhaps you can also assure them that you have no intention of meeting with any of them now as it seems they are deliberately contriving a situation for their own entertainment. Mention that you will go over their heads and inform (whoever they may find threatening) unless (you get an apology) or (they cease and desist the slander of your good name), etc.
There should be some way you could turn this around in your favor. This was malicious intent of feigning "confidence" and involving people who should not have been questioned nor made privy to any personal information. This is truly gossip, slander and troublemaking. Go bite them in the butt!