If you have all the docs make them warranty it. I lost the receipt for my yellow top and I think it was over the warranty anyway, but I'm sure Pep Boys would have worked something out.
The reason I took a chance on Sears was the similar architecture to the Optima, same manufacturer, and if I walk in with a dead DieHard, they pretty much need to do something about it anywhere I can drive to a Sears in this country.
I know, I have walked in on foot carrying those POS DieHards dead and they've had to charge up a new one for me. This happened 2 years in a row before I got tired of carrying a car battery on the subway. This was before they began to brand them "North" and "South" for the change in climate as if that was a good reason.
If you ask me, a battery should not be labeled for a climate zone, it should just perform as expected all around. What if I move or go for a drive? I mean WTF do they think CCA means?