Left my phone in the seat pocket. I'm sure it's still there but I can't get anyone to check it.

I was on the JQ712 flight from Hobart-Melbourne a few days ago and accidentally left my phone in the seat pocket of the flight. I realised this as soon as I can got home and raced back to the airport but was told nothing had been handed in. I asked if someone could check first thing in the morning and gave my seat number etc and was told they would.
When I tried contacting Jetstar in the morning (6am after I left the airport at 1:30 am) I was told that I had to go to the airport and check with the baggage claims counter there.
I did that the following evening as I was flying out of Melbourne back to Dubai in any case. Nothing had been handed in and I was told that I should contact the Jetstar baggage services department as they would send out an email to all airports asking them to confirm if anything had been handed in.
Over 2 days later, I received an email telling me that:
"I assure you that we carried out a thorough search, but I’m afraid your phone cannot be located."
Now I'm not certain that they have even checked the seat pocket. I think they've just waited for someone to hand it in (which they obviously haven't). I'm still pretty optimistic that it's IN the seat pocket because it's one of those weird seat pockets like this one http://i1213.photobucket.com/albums/cc465/Carfield76/Summer2013/file_zps... which are really narrow and deep and you'd have to be sure to be looking for something to know it's there.
The lady at the counter in Melbourne told me they had no way to know where the plane had gone so they couldn't call ahead to the airports to get them to check. Using the magic and voodoo of flightradar24.com, I was able to see that the plane was now in Sydney. I tried to contact Sydney airport who told me to contact Jetstar who told me to contact Sydney airport who told me... Well you get the point. I'm now left tracking this plane around trying to contact an airport where someone is useful and who might be able to jump on the plane and just check the damn seat pocket. I'm hoping it goes back to Hobart as I spoke to a guy there who was absolutely magic and was really helpful (thanks Gavin!) but I doubt I'll see the phone again. The most frustrating thing is that I'm fairly confident I know where it is but I can't get someone to check for me!
Well done Jetstar on being 100% completely useless! I know it's not your fault and it's my responsibility but a little bit of customer care would go a long way.