So I have replaced upstairs and downstairs stems to repair leaking but I cannot replace diverter stems due to both of them being broken and part of the stem is stuck in behind wall. I’ve attached pics showing the new diverter stem and the old one missing part of it which is left in wall. The plastic end piece which is normally screwed on is no longer attached to valve so it is stuck in wall. It’s American Standard Colony I believe. Any help is appreciated. My attempts to pull the rest of the stem out have failed and made the diverter work much worse. Now half the water comes out bottom spout while showering. Many thanks in advance!