If you want to complain to Facebook, go to the upper right corner & click on the down arrow, then click on "Help Center", under the space where you enter a search phrase is a "Give Feedback", click on it and under the first sub-heading is "News feed", click on that & you can complain.
DIDN'T WORK FOR ME - FROM HELP CENTER HAD TO GO TO NEWS FEED THEN FEEDBACK - TOOK A BIT OF SEARCHING.
Lot's of people have posted their dislike for the new format, but sending a message directly to FB is probably a better idea.