Several LinkedIn customers are none to happy with the world's largest professional social network.

In a recent complaint filed against LinkedIn, a group of the social media site's users are claiming the company hacked into their user accounts, collected their contact's email addresses, then used those email addresses for marketing purposes. The suit asks a California judge to ban LinkedIn from continuing to engage in this activity and to force it to return any revenue it brought in as a result of this practice.

A LinkedIn spokesman said the suit is without merit and the company plans to fight it. “LinkedIn is committed to putting our members first, which includes being transparent about how we protect and utilize our members' data,” Doug Madey told Bloomberg in an email.

But according to the complaint, LinkedIn made the members hand over an external e-mail address as their usernames on its site, then used the information to access their external e-mail accounts when they were left open.

“LinkedIn pretends to be that user and downloads the e-mail addresses contained anywhere in that account to LinkedIn's servers,” the plaintiffs said in the complaint. “LinkedIn is able to download these addresses without requesting the password for the external e-mail accounts or obtaining users' consent.”

In a blog post on LinkedIn's site, Blake Lawit, the company's senior director of litigation, says the accusations are simply not true.

“The lawsuit alleges that we 'break into' the email accounts of our members who choose to upload their email address books to LinkedIn. Quite simply, this is not true,” Lawit writes. “We do not access your email account without your permission. Claims that we 'hack' or 'break into' members' accounts are false. We never deceive you by 'pretending to be you' in order to access your email account. We never send messages or invitations to join LinkedIn on your behalf to anyone unless you have given us permission to do so.”

The plaintiffs are asking for class action status on the suit and are seeking a jury trial.

Read more about this story on Bloomberg.

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