This is what I sent JetStar:
Listen here JetStar your flights aren't cheap so don't make it look like we get what we paid for we paid $700 to fly 1 hour 25 minutes from Sydney To Gold Coast My Wife and 3 kids. We do not have passports since we are not regular travelers so we decided to go to Gold Coast for a holiday. Thinking we where booking a domestic flight they would all depart from the domestic terminal No Shit? Actually they depart from the international terminal funny one international terminal and a domestic terminal we are flying domestic obviously we would expect to be departing from a domestic terminal?!?!?!?!
NOW I was told by JetStar it would cost $500 to swap to a flight that is departing from the domestic terminal from Sydney! We will be taking this to consumer affairs as we can not board our flight and your product is not fit for the purpose for which we purchased it!!!
Our hotel booking is on Wednesday we expect something done ASAP!!