I purchased my iPhone 3GS from Vodafone NZ in October 2009 and for some reason, the GPS has stopped working. It doesn't work on apps like TomTom or the 'Maps' application. It just tells me 'Your location could not be determined' Once, it actually found my location: The funny thing is ... I don't even live in Perth. I live in a different country. What should I do before contacting Vodafone NZ for potential warranty repairs?