Ebay Issue After ONE Year

[slidekellyslide]

So two years ago I went to an estate sale and picked up a whole collection of 1950-60s Topps cards including stars...I picked out about 300 of them that I thought were in good enough condition to scan and sell on ebay....ALL of them sold. I get an email from a guy a few days ago who said he purchased a 62 Topps card from me in January of 2013 that came back from SGC as "Trimmed" and now he wants a refund, but I have no idea what he even paid for the card, nor can I even look it up. I am convinced this is a childhood collection that never saw the light of day...not a single customer who bought from me had any complaints at all, and I'm sure some of the people who bought from me sent these cards to be graded as a large majority of what I picked was worthy.

When I told him that SGC must have made a mistake he blew up at me saying they don't make mistakes, they are the most "prestigious" of all grading companies..blah blah.

This is a low feedback bidder who doesn't appear to have done anything on ebay since last June....What would you do?