pull like crazy. Put bars in a vice and then get some pliers and pull it out or you can shove something down there to maybe loosen it or to get it out of the way but only do that as a last resort or you won't get it back.
try pushing it so it twists inside the bars, then stick a long allen key in there and pretty much fish for it. put the little end that sticks the other way in and puulllllllllllllllll. good luck