It should say on your ticket, look for the section headed 'Penalties'. On my D ticket it says "CANCELLATIONS ANY TIME CHARGE AUD 500.00 FOR CANCEL." but also "IN CASES OF NO-SHOW CHARGE NO SHOW FEE OF AUD270 FOR CANCEL"... I don't know why they would make it more expensive to cancel than to no-show, so maybe I am misunderstanding.