May I ask how long they have been inactive?
If they don't care, I would just advise them to do the following.
Don't duck the calls, but don't answer any questions. YOU ask the questions. Why are you guys calling me? Why do you want to meet with me? What is the accusation? Who is making the accusation?
IF there are 2 people (or if they SAY there are), you HAVE THE RIGHT to know who they are. Do not let them tell you otherwise.
If they do not, or do not share info, just say you know they "mean well", but you don't need to have a sherperding visit. (this is deliberate)
They will say it isn't, its a judicial comittee! Well refer to the original questions. I certainly would never appear for a JC anyways, but certainly not one where there was simply rumor and heresay, as well as a desire to already arrive at a certain conclusion.
If it is one person only, perhaps you can ask them why they did not feel that this was just rumor, and why they did not encourage the person to apply matthew 18.
Your friend owes them nothing. They are just some dudes.
Keep us informed, or reach out for more. Take care.