So after my third ticket about missing the Pearl Ring of the Companion I finally get a response. They tell me to "just run the daily ME quest" and that I'll eventually get it, and that there's absolutely no guarantee you'd actually receive this item from the quest it's supposed to come from even though it's a QUEST REWARD and not a drop.
I've gone back and forth with this particular GM for 3 days now. I've provided videos, I've provided links to people complaining about missing this item and ways to reproduce this bug here in the forums, and he or she seems insistent that it's not a guaranteed drop (no HAMSTER, it's a quest reward not a drop!) and that if I just keep running MEs I'll get it "eventually" even though I've run hundreds of MEs on the character that's missing it and have never once gotten any companion gear from it.
As far as I can tell there's no way to escalate it above this chucklehead.
For those wondering, the Pearl Ring of the Companion is supposed to be a GUARANTEED reward from completing the Expedition to Terminus quest (Hot Pursuit). It is not a drop in the expedition, it is a reward given upon completion by Azuli Tefnek.