Doesn't exactly sound legit to return a card that is working fine.
That being said, the SC cards appear to have been discontinued. I'd just make sure you have the card registered within the 30 days, and you'll have 3 years of warranty service. EVGA is excellent with RMAs. In fact, I'm getting my RMA in the mail today, as my standard 670 is having all sorts of problems, including fan noise, screen flickering, and VGA shut downs (not driver crashes).