I'm another one with a cancelled Qatar itinerary. I called up to get my return flight added to an existing booking, unfortunately this meant no-one ticketed it and the reservation was subsequently cancelled by Qatar (30 ish days later).
No call from Qantas, it just mysteriously disappeared from my booking. I have called 4 times to chase to see how it is progressing with no real updates, been promised a callback within 48 hours twice and not called back on either occasion. So I have a one-way booking and half the return journey (with another airline).
I have given up, there was no availability to book something else as Qantas don't release any business award seats to Europe from July to October.
So i've booked with Singapore Airlines and vowed to not fly with Qantas again until they sort their s**t out.
I'm scared about calling up to cancel the return portion in case they cancel the outbound too. So i'm going to call up after i've taken my outbound journey and then probably have to fight with them about that too.
Pretty disappointed tbh.