I know this is off what your question is, but did you buy that through one of the white box promotions of the specials on ebay or did you win a bidding war on a used one? I have been thinking about jumping on one of the white box specials that are posted from time to time and am curious which route you took to get this one. I have seen them listed as white box on Amazon for around the $650 also.
Regarding your question, if you just won it in the bids you might be able to go through the resolutions center of Ebay as suggested. Otherwise, your probably going to have to fork over some cash to Canon to fix it. Hopefully the former is your best course of action and you either get your money back or get that fixed for little or no cost to you. Good Luck!