Game Card issueFollow

hmm, i feel like an idiot, but i guess i scratched to hard on my game card, and i tried to call the tele line, but they are not open on weekends, i still have the box, the receipt, and the game card, im missing like the forst 4-5 numbers of it, should i wait and call blizzard, or should i just take it back to bestbuy for another one, i bought it just last night....please help, im addicted to this game like crack, and the less i play the more withdrawal symptoms i get...