Then your first step should always be to call scheduling first and see what happened. Make sure if they did run the WS step that you were on the TC, and if not yet try to figure out if there were any parameters in your slip that caused you to not get called. If they skipped the WS step then that should be 23m7 to the most senior eligible pilot (probably not you). If they ran WS and you were not properly called then you probably have a case for getting paid for it. Either way no one here can help any further until you contact scheduling.