Have you ever thought about how much trust is involved in consumer transactions? You may do tons of research to find a reputable company with good prices and a great reputation, but there's always that leap of faith when signing the dotted line.

Thankfully, most businesses actually care about honoring your trust. But there are the few nasty exceptions.

What's a consumer to do when charged for a service or product that wasn't received? Or what if the product was defective or the service unsatisfactory, yet the provider demands full price? Here are some of the most common ways to resolve a dispute, save your credit record, and be a pain in someone's behind.

Take it up the ladder -- or at least go sideways
The first step is to talk to someone else at the company. It doesn't necessarily have to be a higher-up, just another person to hear your case (though it should be someone who has the power to resolve your dispute). Call at a different time on a different day, and ask for a supervisor or manager.

This is where all those years of paying your bills on time might pay off. If you have a solid credit score, a company should be reluctant to lose a current or potential customer. Also, a company shouldn't want to risk you passing along your horror story to your network of friends, associates, lackeys, and goon squads.

However, not every dispute can be resolved by a phone call. Sometimes, a letter to people in authority at the business is the better choice. Explain the situation, starting with your biggest complaints, and request a response within 10 business days.

If this doesn't work, document everything you've done so far -- times you called, to whom you spoke, what you discussed, copies of correspondences, etc. -- and get ready to rumble.

Wield your credit card
If you paid for your item or service with a credit card, dispute the charge. Put your request in writing within 60 days of when the credit card bill with the questionable charge was sent to you. You can withhold payment of the disputed amount when you pay your credit card bill (you still have to pay for your other charges). If you've already paid the bill with the disputed item, the credit card company may issue you a temporary credit. The person with the money has the most leverage, so if the issuer will credit your account, you've gained some power.

The credit card company then contacts the merchant and decides who should get the money. If the issuer sides with you, you will not have to pay for the disputed charge or associated financing charges. Otherwise, you're responsible for payment -- and you'll have to take your fight to another battleground.

Sic the government on 'em
Most levels of government have some form of consumer affairs department. Start local by seeing what protections your city or county offer. In most cases, these government agencies can't force a merchant to acquiesce, but they might investigate the complaint and contact the business. Your local government might also offer voluntary mediation and arbitration services. Plus, they keep track of complaints and will investigate a company that has too many unhappy customers.

States also have consumer protection departments, and there's always the Federal Trade Commission. If laws were broken, the appropriate authorities might take action. You'll also get some solid advice from the staff and websites of consumer protection agencies. Plus, the merchant may be more willing to resolve the dispute than to have complaints filed against it on the local, state, and federal levels.

Sic the courts on 'em
If the consumer protection services of the government can't help you, perhaps the legal system can. You could take the merchant to court. This is a complicated issue since rules and regulations vary across the country, so contact your local court system and learn about your options.

Litigation can be expensive and time-consuming, so it's not to be entered into lightly. However, the threat of litigation could persuade the merchant to settle your complaint. If you have cheap access to a lawyer (e.g., you're part of a pre-paid legal service or married to an attorney), a letter written on your behalf might be enough. And, if eligible, you could file a small-claims action, which doesn't require the services of a lawyer.

If the disputed charge is in the thousands of dollars, then hiring an attorney might be worthwhile, though the associated fees will take a huge bite out of any settlement you might receive.

Know when to fold 'em
At some point, you might have to check your ego and determine that it's time to just accept the loss. There will come a point when the aggravation, time, and other costs aren't worth it. Complain to everyone possible, then move on.

Whatever you do, make your voice heard. Besides notifying the appropriate government agencies, warn other consumers by telling your tale of woe on the Internet. Many websites allow users to rate a merchant's service or products, whereas others provide a forum for disgruntled customers. Jump on your cyber-soapbox at sites such as Epinions.com, TheSqueakyWheel.com, AngiesList.com, BadDealings.com, FightBack.com, and even the Better Business Bureau at BBB.com.

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This article was originally published in April 2007. It has been updated by Dayana Yochim. The Fool has a disclosure policy.