I'm not a veteran well guy but I do have the same pitless you describe and have had my pump in and out of the hole a dozen or so times. As you pull on the release cable, it raises the bird's foot and a cam pushes against the casing to eject it from the hole. I repeatedly slap the pulling pipe with the Tee handle sharply against the casing on the side the pitless is on while pulling the release cable. If you're worried about breaking the release cable, you might want to fashion a hook from a length of rebar to get under the bird's foot. It sounds like it just isn't coming up high enough to clear.