I believe that it’s vanishingly rare for it to be “too late” for anyone to change their behavior, on an individual level. If we can recognize the challenge, we can amend our approach and work to bring others into the fold. I’m still grieving as well, but defeatism will only strengthen their position by weakening ours.
Something I like to do is to take their call scripts and mail them as signed letters. Phone calls can be useful, sure (when they’re answered or the answering machine isn’t full or disabled), but my understanding is that written letters are taken more seriously in those offices. The order of significance, as it was explained to me, goes email -> phone call -> letter.