Same thing happened to me. Dealer quoted me about the same price; somewhere near 1k to fix which is absurd. The tiny little plastic tab that holds the button in broke on mine and it looks like that plunger thing is all part of the whole assembly. I finally got fed up of doing the "two handed set the parking brake" procedure, so I finally looked into it and I was able to make mine functional again. What I did was get some plastic weld (it may have been JB plastic weld) or some strong epoxy, and I used a q-tip to apply it to the hole in the silver button that popped off. Put a decent amount in there, but didn't just overload it with the stuff. Then I put the spring back on the plunger and then mashed the button on there. Got myself some duct tape and taped the button down (in the depressed form) by putting a couple strips of duct tape over the handle and the button in varying orientations to make sure the button was being pressed against the plunger and being held there. Left it that way overnight to give the solution enough time to cure. The next morning, I removed the tape and lo and behold the button stayed on! It still moves freely like it always did, the spring keeps the pressure on the button to keep it in the "out" position so it works again like it always did. The only difference I can tell is the button sticks out just so slightly more than it did originally. To me, it was worth it to have a one-handed functioning e-brake again. I can post pictures of what it looks like now if you guys want. I searched and searched for a solution as well and could never find anything, so hopefully my fix will help someone else. Good luck all!