Ok, it kinda depends on what you bought and where... If you bought a real proper card guard at an established shop, you may be able to get it exchanged, if the clip is actually, genuinely, made badly. If it's one minor glitch in the clip, eg a sharp edge, find a hardware store and buy some sandpaper to sand down whatever's scratching it. If the edge is just at a bad angle, well there's not that much you can do really... If you've got extra cards (Jokers, ads), you can try throwing those out, or you can put the cards in just an old box.