G'day , recently I sold a motorcycle on eBay to a guy that lived interstate and did not ask any questions about the bike, did not request any photos of the bike, mind you the bike is a 77 model triumph bonneville , when the owner recovered it via courier he ride it 70kms back to his house as discovered something was loose and a oil leak has come up, not there when I sold it to him or I wasn't aware of it anyway, I offered replacement parts and have ordered them to get to him, that was just before Xmas and in still waiting for the bits to arrive, he has now sent me a text message calling me a fraud and how he is going to take due action , what rights do I have