You can write customer solutions with a copy of you boarding pass and the original ticket printout. You should be entitled to the original mileage as it was an involuntary change, and since they put you up in J (which had lounge access) you are entitled to your $31.50 back. I suspect you'll get sent a MLL pass and should get an additional 232 status miles. One caveat, please change your attitude and don't complain when you write the letter. Just state the facts and ask for what you are entitled to.