Hi I just sold a power supply on eBay and I communicated with the buyer to say I would ship on Friday (3 days after sale) on the listing it said ship within 2-4 days.

He sent me this message:

"Hi mate you still not sent the psu so I've got one now I want a refund it's been to long if you put stuff for sale on eBay you cor just say I'm busy you should stated this that you cor send the item so people know if you don't refund me eBay will so let me know wot you are doing refund or not so I can open case and get my money back it's up to you but I will get my money back so ide just give me my money back as I will get it off eBay I've never lost a case"

This is barely English, but it's apparent he does this a lot as he says "I've never lost a case." He's now opened a return request saying the item is damaged and wasn't in original packaging. Even though it's photographed in original packaging.

What can I do?