Ignition switch

I went to go start my 1996 Lincoln town car signature series and when I turned the key the stuck in the start position so I pulled it back and now it just rotates. Can't shut the car off with the key so I pull the fuel pump fuse and ground wire off battery. I can start the car if I put the ground and Fuse back on. Took cover off column and the switch with the rod is fine but the little plastic slider part that the starter switch rod fits in moves freely. Please help me someone.