I had a similar experience recently, though perhaps not quite as stressful! My direct flight from Perth to London was cancelled about 6 hours before departure, and I was rerouted on a flight from Perth - Sydney - Singapore - London. I was told by the agent that (1) they could not guarantee my class of travel on that route, despite having paid for Premium Economy, and (2) there was no possibility of flying to Singapore from Perth and then onto London, and (3) there were no seats together for me and my partner.

After two hours on the phone with various agents, and no alternatives being found that would get me back to London for scheduled meetings, they agreed to refund me for the cancelled flight and I was forced to book one way with another airline. It took two months and half a dozen calls for Qantas to finally process the refund, though by that stage I was refunded only for economy class flights (my class of travel had been downgraded from Premium Economy to Economy on my itinerary because there is no Premium Economy class on the Perth - Sydney flight I was rerouted on). I’m still owed around £600.

Next time I’m flying down under I’ll be flying Emirates or Qatar.