Lost luggage

I travelled from Melbourne to Hobart today. After checking in I realised I had been given a baggage receipt with the wrong passenger name and city on it. I then went back to check in and showed the girl who checked in my bag the receipt. I was assured that my bag had been correctly booked under my name and would be on my flight to Hobart and that I had just been given the wrong receipt. Well, I arrived in Hobart, no luggage and now no one at Jetstar can tell me where my luggage is!!!! How can a bag just vanish when you fly a single flight from Melboure to Hobart? Appalling customer service!