The items you purchase come with guarantees that cannot be excluded under the Australian Consumer Law.  You are entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.  In the case of a major failure, you are entitled to a refund and compensation may also be payable for any other reasonably foreseeable loss or damage.  Action to remedy the problem may include instructions on proper use.  You may be required to supply the goods for inspection or provide pictures or videos of the defect so an assessment can be made.