So you definitely didn't make it into the flight you were confirmed on (Yikes). When did you ultimately get to your destination? How long was the total delay?

The only analogous story which immediately comes to mind is http://www.flyertalk.com/forum/unite...3-new-low.html , which was NOT the same (United oversold first class and downgraded a paying J pax because the rest of the occupants were GS) but which felt a LITTLE bit similar because there, too, lobby check-in agents spent a very long time, very close to the check-in cutoff, handling the passenger. That particular incident reportedly sparked a lot of internal investigation at UA.

I hope that the situation you have described here is resolved to your satisfaction and United makes the appropriate policy changes to prevent this from happening again. This is really really really bad. You should absolutely escalate this.

At a bare minimum you are owed IDB compensation for all pax (cash, 3x one-way fare value up to the regulatory limit). There's no way "pax presents at kiosk in time, UA delays check-in then offloads the pax" is okay.