Within hours after the Coca-Cola Co. announced the birth of New Coke, telephones at the soda pop giant's corporate headquarters in Atlanta were ringing off the hooks.

Irate customers were enraged the company would arbitrarily cast aside the old favorite without asking the people who had purchased it.

"We asked many of the callers how long they had been drinking Coke," recalled Roger Nunley, manager of industry and consumer affairs at Coca-Cola USA. "Some of them said, 'Oh, I don't drink Coke.' So we asked them why they were complaining. They said, 'It's the principle of the thing.' "

The calls continued for weeks. Before New Coke, the company averaged 400 calls a day to its toll-free consumer hot line; after New Coke was unveiled, the number bubbled to more than 12,000.

After what must have seemed like an eternal public flogging, Coca-Cola officials relented. Company executives cited marketing studies, ledger sheets and other business hooey as the sound financial basis for their change of heart.

But they also admitted the thousands of phone calls from infuriated customers were the overwhelming factor that convinced them a mistake had been made.

Said Nunley: "Those were the angriest consumers we've ever run into."

That 1985 episode at Coca-Cola, although unique in scope, clearly illustrates the power of the consumer.

When a company as big as Coca-Cola sits up and takes notice of its customers, it is plain to see the consumer movement is flexing its muscles as never before, in the finest tradition of Nader's Raiders.

But what about the little guy who bought a lousy toaster? Is there hope?

Yes, the experts say, but it's all in how you make your beef.

"If you know how to approach a company, a government agency or anybody who has wronged you, the odds are you can get more out of them in the long run," said James Thompson, manager of consumer affairs for the American Association of Retired Persons. "The basic thing is knowing who to complain to."

But there also are the elements of when, why, what and how -- when do you complain, why are you complaining, what do you want done about your complaint and how you should complain -- and the nerve it takes to gripe.

Many complaints about a product or service can be satisfied at the source. If you purchase a faulty toaster or the bank loses your savings account, the problem might be resolved by contacting the salesman or bank representative. That is the simplest approach and often the most effective. At the very least, experts say, give it a shot because the road gets more bumpy from there.

If the situation is not resolved at that first step, the next step is a manager or some other "person in charge." An even better alternative would be the customer service department, which has become commonplace in most companies of any size and employs people who are paid to listen to complaints and come up with resolutions.

If you still have not received satisfaction, it is time to contact a third party -- the Better Business Bureau, the local consumer protection agency or maybe even a lawyer.

Of course, the cost in time and money becomes greater as you work your way up the complaint ladder and it must be remembered the potential satisfaction, if you are successful, might not increase comparatively. Make sure your gripe is worth the trouble.

The best way to achieve your ultimate goal -- getting your problem resolved to your satisfaction -- is to carefully organize your thoughts, convince yourself once again that you are right and proceed in a determined but civilized manner. And put everything in writing for future reference. If your complaint is presented in a professional manner, it has a better chance of being handled in similar fashion.

If a simple phone call or visit does not resolve the problem, it's time to write a letter. Make photocopies of all receipts, warranties or other documents related to your dilemma and then construct a letter that cuts right to the heart of the matter.

"Tell them in the letter what the problem is," said the AARP's Thompson. "But the most important thing the letter is saying is what you want. Do you want a refund or a visit from someone? That type of letter is what consumer affairs professionals tell people to do. It sets an agenda and puts the situation in a solvable position."

If writing a letter fails, there is always legal action or the threat of it. If you are really irritated, a little public embarrassment can go a long way.

"If everything else fails, we might even suggest that people put the product in front of their house with a sign on it saying, 'Don't buy this product because it doesn't work,' " said Thompson. "Then take a picture of it and send it to the company."

The worst thing an aggravated consumer can do is keep quiet and go away mad. That's more typical of older citizens, Thompson said, since they were not raised in the dawn of consumerism.

No matter the age, such inaction is fair neither to the consumer nor the company. That's right -- companies want to hear customer complaints. Or at least, they say they do.

"You do a company a disservice when you cease to do business with them without telling them the reason and giving them an opportunity to correct it," said Robert Dowling, professor of management at California State University, Dominguez Hills.

The people on the other side of the complaint window have changed over the years. At one time, they were poor souls relegated to the job of listening to customer gripes. Some were nasty and some were kindly, but few were trained.

Now there are professional people and entire departments with the sole objective of keeping customers happy and solving problems.

To see just how much the profession has grown, there is no need to look farther than the Society of Consumer Affairs Professionals in Business. When it was founded in 1973, this national organization had only 100 members. Now it has more than 1,500.

"In the last 10 or 12 years, there has been more emphasis on corporate consumer affairs," said Cindy Grimm, director of professional development for SOCAP. "When the consumer movement first started, it was mostly advocacy groups. But in the last few years, big business has determined it is good business to take care of the customers."

Studies in the past indicated businesses did not hear from 49 of 50 unhappy customers. Many people figured complaining was too much of a hassle and the chance of actually getting what they wanted was small. As a result, most of those customers stopped using the particular product and switched without ever complaining to the company. As the age of consumerism has flourished, further surveys show customers who have filed complaints with companies tend to have even stronger brand loyalty -- even if their gripes were not fully resolved.

"The key thing," said Coca-Cola's Nunley, "is getting the other 49 consumers in the front door."

So companies such as Coca-Cola have started toll-free customer hot lines, published "how-to-complain" booklets and instigated other consumer education programs. Businesses have decided they do not want agitated customers because it costs them money in the long run.

A more recent Coca-Cola study demonstrated the impact of the word-of-mouth phenomenon, showing customers who have a good experience with a company tell an average of five people, but customers who have a bad experience tell nine or 10 people. With increased competition in all fields, no company can afford such bad publicity.

For companies, the main thing now is letting consumers know how much they care.

Said Grimm, "The old saying 'The customer is always right' is not always correct obviously. But certainly companies are paying more attention to what the customer is saying. With competition getting tighter, every company is looking for an edge. Listening to the customer is a good way to find those edges." For a free booklet that provides a listing of federal, state and local government agencies, and private businesses and organizations that can help resolve complaints: Consumer's Resource Handbook, Dept. 579L, Pueblo, Colo. 81009 United Press International