I have seen bunnings refuce any kind of refund on them they keep telling the poor owner to take it to an authorised repair place for warranty, pretty sure if you want your money back on it you have to take it back within 2 weeks.

On the other hand here though I have a mate that works at mitire 10 selling thesame thing, he has had afew angry people come back when they have not filled the oil and getten even angrier when they get refused a refund since they ignored the labels everywhere that says fill the sump before use.