I did see your question and matched your speculation with my own to demonstrate the point that it doesn't help your argument to King's people. There's not enough information for any of us to do anything but guess. Do you think his people really want to entertain publisher conspiracy theories?
I totally understand your frustration and would be pissed in your situation as well, but I think your letter could be a lot stronger. That's the only reason I took the time to respond in the first place.
Grant obviously screwed up and should have done a much much better job dealing with your issue. Send a physical copy of your letter to Robert as well when you send it to King's office.
Good luck.