Man, that's a bummer. Maybe you'll have better luck with SQ or the ME3? I met many many Brits on a cruise out of Sydney, and being an FT'er of course I asked about their flights. I kept hearing "Emirates" (in Y).
Maybe your coworker could call up again, and say "I'm actually calling about my colleague..." and see what the response is? It's not exactly the same but when I call AA's Platinum desk they have helped with my wife's tickets. Were your colleague's tickets booked at the same time? Due to availability, perhaps his ticket ended up being a different fare?