FWIW, I have recently used the cashback on eBay on three occasions. In an instance where an item was listed for a couple of days before I found it, I got my cashback INSTANTLY. In both instances where it was a setup (from SF), they are showing as Pending, and will probably take 60 days. This
thread talks about someone who has had problems with setup auctions, and may not get their refund AT ALL.
Don't get me wrong - I do it myself, just a FYI, and something to look out for.