OK, but there has to be some order of priority of making the calls. They can't make 400 calls simultaneously. I'd suggest a P1 travelling in F should be the first one called. Then other pax in F. All these pax should get absolute priority because their class of service disappeared on the subbed aircraft.
Then a P1 in J. Then other pax in J (WP, then SG, then PS, then NB, then other).
Then a P1 in W. Then other pax in W.
Then a P1 in Y.
So the OP - travelling in Y - would have been a fair way down the priority list.
And that's only if you believe that every pax should be contacted, in a situation when the only thing that changed was the aircraft type - flight number, departure date and time, seat class, seat type all stayed the same.