Volkswagen Polo 2011: Faulty airbag

Over the past 12 months there have been six occurrences on my daughter's Volkswagen Polo TDi where the faulty airbag warning light has come on. We have had three new airbags, a clock spring replaced, and a new wiring loom. This airbag will not deploy in an accident and Volkswagen is continuing to ignore our requests to recall this vehicle as we feel it is a major safety issue. They either fail to respond to our correspondence or simply advise us to return the vehicle for further diagnostic testing. We are repeatedly ignored by Volkswagen. We have now submitted a formal complaint to the NSW Department of Fair Trading as Volkswagen are still failing to advise us of an outcome. Where do we go from here?