The best place to start is with the company itself. That's where you're likely to get the fastest satisfaction. If you can't get help from a supervisor, go right to the top. How do you find the head honcho? Scour the firm's Web site or annual report for the chairman, chief executive officer, and the like.
Let the company know that you want to resolve the problem, but you are also interested in remaining their customer. If you act angry or threatening, the company may not help because it already knows it lost you.
If your complaint doesn't get any action, you have to go outside the company. The best place to start is with the local consumer protection agency. Often that's either a consumer protection department or the state attorney general. Also try the Better Business Bureau at www.bbb.org.There you can file a complaint online.
If all else fails, Consumer Reports says a sure way to have your complaint taken seriously is to file a lawsuit. Small-claims court is a good choice for smaller cases.