Flight changed due to airline error

I booked to fly Perth to Christchurch. At the last minute the flight was moved forward 2 days. I rang to find out why and was told there was insufficient time to transit to a second flight in Melbourne. I pointed out that this was Jetstar's error as these were the flights which were automatically selected when I booked. I advised that I was due back at work and unable to remain in Perth, so the flight was refunded, A last minute booking with another airline then cost me an additional $700 odd dollars. Even with the new flight I also needed an extra nights accommodation in Perth. The live chat customer help suggested that this was "the nature of air travel" however this wasn't an unexpected weather event etc it was a clear error on the airline's part. Very frustrating couple of hours trying to communicate with the airline also.

New Zealand-Christchurch