How to deal with a refund request when the item 100% worked when shipped?

[samsmoke]

Hello,

I recently pulled a perfectly working video card out of my system, stuck it in a box and listed it on ebay as no refund. The buyer is saying the item does not work. They have requested a refund. Ebay seems to make it appear as if I have to refund the money. The only option I have is respond to the buyer. I'm not a store/company and how do I know the buyer didn't blow up my video card when hooking it? If thats the case I definately don't want it back.

So how do I handle this?

Do I have to refund the money? What happens if I refuse.

If I decide to take the hit and refund the money do I still have to pay the listing fees/final value, etc?

Thanks for your help.