Hey people, I just found a thread on another forum (which I will not name here) regarding this, which makes it look even more likely that YT is in process of killing QG as a YouTube network; if you look at the thread, the reason will be obvious. Google "Quizgroup unlinking channels" and you will find that thread near the bottom of the first page of results.
There a couple of other things QG members can do. One comment from each unlinked member to the discussion thread on the actual QG channel would be quite a few comments indeed, and has a microscopic chance of getting their attention; I started you off, though I am not a QG member myself. And I just found out that someone has actually started a petition on Change dot org regarding the situation. Don't try the Google Product Forums, they have already proved they are less than useless; telling the QG members who came there asking questions to "Contact Quizgroup support for this matter". I replied to the forum mod who said that that the QG members were coming there because QG Support wasn't answering member emails.