No duty of care from Jerstar

My American aunties (x4) and uncles(x2) came to Australia to visit me, they are all senior citizens with the youngest being 65 years old. Within Australia, they flew domestic from Sydney to New Zealand (Jetstar.. Delayed) then from New Zealand to Melbourne (Jetstar... Delayed). On the way home at the end of their holiday, they had prebooked Jetstar from Melbourne to Sydney leaving from Avalon Airport as it had the first flight out to Sydney at 6am. Taxi fare to Avalon $130. They arrived at Avalon at 4am only to he later told that their flight had been cancelled. Their English is not too fantastic and had a hard time explaining that the had a connecting flight to Los Angeles from Sydney. Nothing Jetstar could do they said only rebook their ticket but it will be leaving from Tullamarine Airport. My elderly relations had to take another taxi to Tullamarine costing $140. No offer of transport was offered to them or were they even reimbursed/voucher for the taxi. They waited 3 hours in Tullamarine and arrived at 11.49am in Sydney. Their connecting flight has left on schedule at 10.18am.

My relatives called me all frantic as they didn't know what to do. There is no American Airline counter in Sydney to talk to. The airport staff told them that they had to buy new tickets and do it online. That would mean that they had to buy 6x tickets to LAX then 6x tickets to NYC then 6x tickets to Newark Airport. All these tickets would be last minute tickets that would cost an arm and a leg.

I called up Jetstar for a "please explain" they kept me on hold for 2.20.42 hours before I was "suddenly" disconnected. I'm furious how they cam get away with this kind of behaviour and getting away with no repercussions for what they are putting people through both financially and emotionally.

How can we let this go on? Why have we not done a class action suit against them? I will keep going with this, because of their actions they had put my elderly relatives into financial hardship.