Ask them who is making the accusation. Then tell them that you have a biblical right to have that person accuse you in person.
That'll leave them stammering for a minute. They have to concede that to you. They must have the person make accusation in front of you unless you confess.
My suggestion: Don't confess. Treat them as equals both intellectually and spiritually. Do not treat them like they are your superiors. Do your homework on how they are instructed to do their process. They will screw it up because they are ignorant.