If they say stop, stop.
 
Even if it's unreasonable as whether you're right or wrong, at that point you've already lost and if it's that important, make sure you write a factual letter as you know they absolutely will.
 
The calmest, most reasonable voice wins. The crewmember won't hear a thing about your angry letter and they'll probably throw some "quiet miles" at you, at best wash their hands of the situation and continue taking care of the other tens of millions of passengers that seem to get to the airport, onboard, deplane and don't require any extra attention.