It's the right thing to do to warn others on the board. It's selfish on your end to not want to reveal their name "in hopes they see the thread and get scared" and pay you. If they are secretly changing their terms to you and if they are a big "well known company", think how many smaller affiliates they are basically screwing over just like they are doing to you.
You would be doing a disservice to others on the board by protecting this company. If anything, you outing them would make them pay you faster because it would damage their reputation that they are raising the minimum payout from $50 to an absurd $1000. That's a sign of shady business practice no matter how big the company is.
I had no problems outing AshleyMadison a few months back here:
https://gfy.com/fucking-around-and-pr...son-shady.html
even though I promoted them and did well with them.
By outing them, you would be helping existing affiliates unaware of this new payout change and new affiliates that was thinking of promoting that program.