1. Avoid hostility. Remember: You're dealing with human beings, not computers. Be as polite and as firm as possible. "Give yourself 24 hours to calm down," says Ron Rosenberg. "The person on the other side of the counter can either help you immensely or say, 'Nope, I'm not going to do a thing for you.'"

2. Don't give up. After your call has been endlessly transferred in an extensive phone tree, it's easy to just hang up. Unfortunately, that's what many stores count on.

3. Keep documentation. If a store treats its gift certificates and merchandise credits as cash, all the pleading in the world won't get your money back without some documentation.

4. Don't wait. Unless the merchandise doesn't work or doesn't last, most companies have 14-day return policies, which means you need to act fast. And you're always better off taking action when events are fresh in your mind.

5. Know the facts. Before you storm the store and demand your money back, know what you're dealing with. Call the store and find out return/replacement policies and the managers' names. If you're prepared, you'll be able to argue your case in less time.