In contrast with the OP, I have consistently found QF phone operators to be friendly, professional and competent.

However, I would not expect a QF phone operator to be skilled in the details of a complicated product like xONEx tickets. Even AA have established their RTW desk with specialist staff for this.

I would have thought there was enough text on FT to say two things:
1: use the OW RTW tool for xONEx tickets
2: use the AA RTW desk to set up these and similar itineraries