Robert Galbraith / Reuters

Dozens of Facebook users wanted answers about why the company had abruptly suspended their accounts. They sent messages explaining that they did nothing wrong and demanded that their access be restored.

But Facebook’s customer service ignored their pleas or replied with form letters. Frustrated, the users took action: They filed complaints that ultimately ended up with the Federal Trade Commission. “I want answers to my questions,” one user from Dimondale, Mich. wrote. “I want a valid phone number or e-mail address that will be answered.”

Blocked accounts are just one of many grievances Facebook’s legion of users have voiced to the F.T.C., the agency responsible for enforcing consumer protection laws. Aggrieved, annoyed and occasionally misguided, Facebook users lodge more than a thousand complaints annually about everything from alleged privacy violations, technical glitches and billing problems with their advertising.

The complaints provide a window into the formidable challenge of keeping more than 1 billion users happy. They also show how Facebook’s customer service is a source of frustration for many people, who grumble about receiving canned responses to their emails—or none at all—instead of individual attention and immediate help.

The F.T.C. provided consumer complaints against Facebook for 2012 in response to a Freedom of Information Act request. To protect privacy, the agency redacted the names of people who complained and information related to law enforcement investigations. The list included complaints filed directly with the F.T.C. plus those forwarded to it from outside sources like California’s Attorney General and the Better Business Bureau.

A Denver resident groused that Facebook ignored a request he made five months earlier to shut down his deceased mother’s account. An employee of a counseling center in Fort Worth Tex. accused Facebook of over-billing for advertising to the tune of $800. Yet another person from Shelby Township, Mich. griped that someone had opened accounts using risqué photos of his fiancé and that Facebook failed to delete them after he had repeatedly asked the company to do so. “It has become hard for my fiancé to leave the house because of the fact that people recognize her from the photos that are being used, and she is being harassed by people because of it,” he said.

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The F.T.C. received 1,655 complaints related to Facebook in 2012, down from 2,171 a year earlier. The company had 1,381 in 2010. The level of discontent is likely much higher because many people who have problems don’t bother to file a complaint. Of course, those numbers are still minuscule compared to social network’s legions of users.

“With more than a billion users and a million weekly reports, it takes time to investigate an issue and we are sometimes going to make mistakes,” Monika Bickert, global policy manager for Facebook, said in a statement. “Facebook is constantly evaluating its processes to improve customer service.”

Facebook has hundreds of people dealing with customer service issues and enforcing rules around the clock, seven days a week. Workers in the company’s Menlo Park, Calif. headquarters, along with teams in Austin, Tex., Ireland and India, field problems from across the globe and in a cacophony of languages. Staff triages issues based on their urgency so that a suicide threat, for example, takes priority over someone whose profile is blocked. The goal is to take care of most problems in hours or days, not weeks.

Telephone support would be impractical given the number of Facebook’s users along with being less efficient, according to the company. Users can avoid getting into trouble or find solutions their problems by reading Facebook’s extensive service’s community standards policy, visiting the online help center or checking out the help forum where users answer each other’s questions. If the volume of e-mails about a particular topic suddenly increases, the company tries to respond by adding information about the issue to its online resources.

Facebook is by no means a leading target of consumer ire. In fact, purely online companies are completely absent from the F.T.C.’s top 20 list of the biggest sources of customer despair. “Credit card services,” a broad category encompassing an array of financial services firms, led last year’s rogue’s gallery with 321,496 complaints. The first specific company on the list was T-Mobile at No. 9 with 46,392 complaints followed by Bank of America at No. 10 with 45,262.

The F.T.C. invites consumers to file grievances about any company that they suspect of fraudulent business practices, and hundreds of thousands of people use the system annually to voice their displeasure. Few large businesses escape the public’s wrath.

When consumers vent to the government about Facebook, it tends to be about very individual matters. Most insist that Facebook screwed up and failed to fix their problem, or they feel personally wronged in some way. The complaints also highlight how seriously people take social networking, which Facebook has turned into a multi-billion dollar business. Being blocked from sharing baby photos or playing video games through the service is cruel and unusual punishment, judging from the dire language many people use in their complaints.

“I don’t know how to explain to my friends that I am not on the site anymore as I was deleted by Facebook!” someone from Ashland, Mass. complained after being suspended—unjustly, the user said—for registering under a fake name. “How embarrassing!”

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The F.T.C. can use the information it collects to open investigations and prosecute wrongdoers. However, many of the complaints it receives simply reflect poor customer service—not fraud. In some cases, the agency forwards complaints to the companies targeted so they can take a stab at fixing the problem.

The complaints provided by the F.T.C. did not include those filed by public interest groups like the Electronic Privacy Information Center, a frequent Facebook critic. Such organizations typically have other more direct channels to voice their concerns.

Whatever the case, Facebook is frequently in the F.T.C.’s crosshairs. Two years ago, the company settled accusations that it published user profile information public without consent. Last month, the F.T.C. launched yet another probe, this time over revisions Facebook made to its privacy policy. The changes, denounced by privacy groups and teen advocacy organizations, let the company insert users’ names and photos into ads without their explicit consent.

Despite the attention regulators pay to privacy, consumers voiced only occasional concern about it in their complaints. Relatively few people mentioned the topic, and those that did focused largely on obscure issues. Privacy groups generally explain the disconnect by saying that most people fail to realize that extent of online tracking. If people knew, they’d complain a lot louder, the groups say.

Of those Facebook users who did complain, a handful railed about the service requiring them to provide copies of a government issued ID to reopen their accounts after they’ve been hacked or to prove they are using their real name. Others seemed confused about the options for deleting their accounts—withdrawing their profiles temporarily or completely erasing them—and assumed that Facebook had failed to follow their wishes.

Only one person, a woman from Pittsfield, Mass., went into a detailed diatribe against Facebook’s tracking of users. In particular, she called out the company’s requirement that users who log in have cookies enabled on their browser – a necessity for tracking them online. “They are basically NOT allowing you to use privacy settings that are built into your browser,” she wrote. “I do not want Facebook using my information to target me for advertising nor do they have any business tracking if I go to any other Web sites after or before visiting their page.”

Some complaints, however, border on humorous, although the filers seem deathly serious. For example, someone from Stratford, Conn. saw nothing wrong with posting nude photos and attacked Facebook for twice suspending his or her account in the past month. “My family is nudist,” the user wrote. “I don’t see a butt as being pornographic.”

Several people complained to the F.T.C. about Facebook’s initial public offering two years ago and the poor performance of its shares immediately afterward. The topic isn’t really an F.T.C. matter, but rather the domain of the Securities and Exchange Commission. Still, several Facebook shareholders saw fit to voice their dissatisfaction like one from Hackensack, N.J. who asked for a $4,662 refund on the investment. The company’s shares have since rebounded, however, and early investors who held onto them are now in a position to earn a tidy profit.

Only a small number of people whose complaints ended up with the F.T.C. offered details that could allow them to be tracked down. So it’s impossible to say whether Facebook’s customer service ever resolved their problems.

One complaint that could be traced involved the Forward Thinking Museum, a photography Web site for artists. Facebook abruptly suspended its account without any explanation in September 2012, according to Peter Fahrni, the museum’s director. He said he sent two appeals over a period of a few weeks. A month or so later, Facebook wrote back suggesting that the museum violated the service’s rules by paying off someone to increase the number of “likes” or “subscribers” to its page.

“I can state with absolute certainty that nobody in our organization has ever engaged in obtaining “Likes” or “Subscriptions” through paying anybody anything,” Mr. Fahrni replied.

He explained the unusual increase as a welcome consequence of artists in a recent exhibition telling their friends about it. Facebook eventually responded by leaving an unannounced note in the page’s administrator panel saying that full access would be fully restored in 10 days. In all, he said the museum lost access to its Facebook page for two or three months. The experience left him bitter and dissatisfied with Facebook’s slow response and lack of an apology.

“It was nerve wracking, because I could not get through to a human and felt there was no recourse,” he continued. “I’m not sure to this day if I had a correspondence with a robot or a human being.”