Scammed by a buyer - returned item for free use. I got owned

[johno4567]

So I sold my drone on ebay.

Buyer uses for a few weeks then starts a request saying he wants a return as the item is defective. Before I can respond the request is cancelled and a case is started. The case is then on hold. I have no idea what is going on, I email him to tell him the drone wasn't defective the issue he is having is new but I googled the problem and it looks to be an easy fix. I never get a chance to respond to ebay and the case is decided in his favour. I'm so confused... 

I don't mind getting the drone back because I saw the problem is easily fixed. But I seriosuly loose out.

I pay for postage ($40)

I pay for ebay listing fee ($75) - maybe I can get refund?

I pay for return postage ($?) - he requested this in his case and because he won I guess paypal will take more money?

I can't believe this, he effectively got free use of my drone for a few weeks, returns it for some bullocks reason and I pay for return postage.. 

Surely this is a scam? I will hopefully never sell through ebay again....