O.k. get a can of penetrating oil. Not WD40 and soak the post real good. If you can't get it to go down on top then take out the bottom bracket and go that way. Let it soak in for a few hours. Get a wrench like a large channel lock that reall grips the post and twist back and forth till it moves. If you don't care about the frame and just want victory get a torch and hit up the part that the post goes into and that will loosen it up. It will ruin your paint job though.