Is the extractor in the slide?
Have you tried gently pulling the extractor back a fraction of an inch to release the plunger.
The extractor locks the plunger in place and has to be moved back slightly to unlock the plunger.
The extractor is out insert a small screw driver into the slide and push the plunger out.
If it is in the slide, put some Kroil around the plunger and let soak over night, then try tapping the slide on a table top covered with a piece of thin cardboard.
If that doesn't work, you may have to drill a hole in the plunger and use a punch to pull it out.
