That liner grab is the absolute worst, I felt that whole story in my gut. Last spring I had almost the same thing happen, my brush head spun right off the cable about 15 feet down on a steep pitch. I ended up using a long piece of stiff wire with a hook bent on the end and fished around for an hour before I finally snagged it by the bristles. Felt like winning the lottery when I heard that metal clink against the flue. Did you have to pull the whole liner out after that, or were you able to get it moving again?