OP voluntarily off-loaded himself from a flight, did not make alternate arrangements although he was in contact with what he termed "helpful" staff and later sent an offensive demand to the carrier.

He has already made a "donation" and it's all over and done.

It would not have been unreasonable for OP to have asked to have his ticket cancelled and refunded because no alternative routing could get him to his meeting, but he apparently did not do that. The requests for J and for reimbursement of his travel back home are simply not in the cards either.

A smarter approach if one finds oneself having to write in after the fact is to simply state the facts and ask for a refund and leave it at that.