The ACCC guide to debt collection. Section 12 is useful and so is section 19.
http://www.accc.gov.au/content/item....int%202010.pdf
The operator then cuts off all lines of communication with the ex pilot, never reply to emails , won't take your phone call or even reply when you have left several messages.
The solution to that is a registered letter addressed to the CEO of the organisation or failing that the CFO.