Can buyer message saying item works 'perfect' on receipt then say defective nearly 1 month later?

[*goodbuys*]

Private seller here. Sold used item. Buyer ebay messaged me on receipt to say they tested it and it works perfectly. Left me good feedback. Suddenly on the eve of the 30 day window I receive a message from eBay saying buyer states it's defective/doesn't work and an auto return had been initiated. He didn't reach out to me but sent me a message after actioning the return with the same fluff he wrote in the return case - essentially he's been using it sporadically over the weeks and it no longer works.

It has just been returned to me, now no longer working as it had been when I sent it. I have a couple of days to act as ebay are pressuring me to refund him. Yes, I do offer 30 day returns, but isn't he (fairly new member) violating a bunch of policies - false reporting, USING an item before returning, exploiting money back guarantee, etc? Any advice - large or small would be greatly welcomed. Thanks so much for reading.

[tsmgmd]

A private seller on eBay has one legal obligation. 

The item description must be 100% accurate.

But we are talking here about eBay whose Money Back Guarantee in effect removes your rights as a private seller when a malicious claim is made. 

You could speak to eBay on live chat explaining that you have a message from the buyer saying everything is ok

[john1297576]

I can see no evidence on his ID of any sales or feedback for selling, which does not help at all as it sounds as though you are a Business Seller and would have to accept a return for any reason.

Ebay will support the buyer and if you do not refund, the buyer can escalate to ebay and they will at your expense, you get a damaging defect on your account and NO refund of the selling fee.

Fair, NO, but that is one of the risks you run when selling on ebay.

After you have refunded you can appeal but it will not get your money back.