Well this person is saying that they never made the flight. The bags left the point of origin and were back in Europe before he/she was.
If Halo had got to the aircraft after just making check in before it closed and their bags didnt make the hold/bins etc then they stay where they are and get rushed out on another flight.
Seems the other way round though. Delta appear to have been fibbing. The flight shouldnt have left with those bags on board without the proper screening which is sounds like they didnt get. On the delta flight anyway.