Eaglesteve, surely you have consumer protection laws in Aus? The device is clearly not fit for purpose, therefore breaking the terms of your contract
In the UK all major retailers will try to sell additional cover or insurance; although the consumer protection act makes them legally obligated to repair or replace electrical goods for up to 5 years after the date of purchase. My point; retailers rely heavily on consumer ignorance
You didn't purchase the device directly from samsung, the store can't absolve responsibility by claiming to be a "middle man".. plus most sales assistants know jack **** about the legalities of your agreement.
Write a formal complaint to the retailers head office, send the letter via recorded delivery and state that you've been advised to provide a response period of 14 days before taking your complaint further. You don't want to look for a replacement, make it clear that it's a manufacturing fault and not specific to your device. There should be an AUS ombudsman that deals with consumer complaints (bit.ly/8Xl55G), find the correct governing body and lodge a formal complaint, they should provide a reference for your case; include it in the letter to the retailer. In the UK you would then be able to take your complaint to the small claims court, however most companies will **** bricks and fold before it reaches this stage. The bottom line is the device was sold to you for its GPS capabilities, the information provided by the retailer mislead you to into the agreement; you've signed up under false pretences, reason enough for the contract to be declared void