I guess you haven't left feedback yet either, seeing as how he has 1 feedback and it's positive. Post up the negative feedback AND contact eBay. Maybe your feedback will keep others from getting ripped off.
I would wait until 89 days after the auction is over to file your negative feedback. That way he won't have much of a chance to retaliate against you for the negative. I would also watch his user ID for any future auctions and if he posts any more software I would warn other bidders about what happened with your auction.
89 days means NOTHING regarding feedback.
ebay's policies are to *start* removing auctions once they've hit 90 days. This does not mean however that an auction will be removed exactly 90 days, 0 hours, 0 minutes, 0 seconds from the time it ended. It does mean that it goes in a queue to be removed the next time eBay runs code to remove auctions.
I have personally seen auctions out there as long as 120 days. Typical is 95 through 110 days. It depends on the category and item number. If you notice item numbers start with different digits now. This depends on the category they're listed in, and on which server they're stored on. Therefore 2 listings the same night may be removed on totally different days down the road.
You CANNOT depend on the 90 day rule. You can check similar item numbers in yours or others feedbacks to see when the get unlinked and get a closer idea when one may be deleted, but again, it's a crap shoot, you cannot exactly guess.
Also, waiting 90 days to leave negative only allows the seller to continue their ways and scam numerous other people and gives you a lot less pull with ebay (not that you have much anyway, but that's another gripe for another time) since you don't have something documented against their account.
File a square trade report, and if you paid by pay pal, IMMEDIATELY file a report with them. (before 30 days is up) and leave negative feedback now and contact ebay Fraud and file a report with them.