provided you reached your destination two hours or more later (I think this is the cutoff now) you should be due IDB compensation. write in to CS, calmly but fully explain the situation (your post here was a little bit fervent, but rightly so) and request IDB compensation citing the fact that you were unable to occupy the seat you purchased and the COS was not IDB'd as should have happened. i may be mistaken but i think IDB compensation is to be in cash or equivalent, and not in airline credit. others might correct me.