I could be the last person to be aware of this but have just cancelled some very cheap tickets (ticket $32.00 taxes $100.00+) and will be getting tax money back in 7-8 weeks (supposedly) as long as I send a letter to Jetstar to confirm cancellation and request the refund of taxes paid. Previously when I have rung Jetstar to enquire about what I can do with my tickets nothing was mentioned of tax being refunded so rather then money lost will be more to spend in Bali the reason I was cancelling one of the flights...very happy!