Uh, same question..... if you only had it three days and there is a problem, you should not be getting a refurbished one in the mail. You should just take it back and get a brand new one. Unless of course, you bought it online through like let's talk or wirefly , cuz then of course you would have to get a replacement in the mail.
Anyway, back to the op question. From my understanding the little void indication next to the battery is on or attached to a screw or something. Basically it is just warning you that if you mess with that, you void the warranty.