I recently sold a bunk bed on Gumtree. The guy checked the bed and confirmed that it was as described, and he took it away. However, when he came back, he asked me to go to his place to show him how to assemble the bed. He also threatened me that he would call the police if I don't help him with it. Am I responsible for this under Australian Consumer Law? I am a private seller on Gumtree. Could you provide me some legal answers for this?