Facebook Inc. (FB - Get Report)   traded lower for a third consecutive session Wednesday as the fallout from the social media group's connection to a shadowy U.K. political consultancy continues to hammer its reputation amid calls for its founder and CEO, Mark Zuckerberg, to face lawmakers on both sides of the Atlantic.

British parliament's Digital, Culture, Media and Sport Committee has written to Zuckerberg and demanded he appear before the subset of U.K. lawmakers by March 26 and answer questions with respect to his company's connection to Cambridge Analytica, the London-based consultancy at the heart of a data mis-use scandal that could have had potentially swayed the outcome of the 2016 U.S. Presidential election. 

"Your officials' answers have consistently understated this risk and have been misleading to the Committee," wrote U.K. lawmaker Damian Collins. "It is now time to hear from a senior Facebook executive with the sufficient authority to give an accurate account of this catastrophic failure of process ... Given your commitment at the start of the new year to 'fixing' Facebook, I hope that this representative will be you."

Facebook shares fell 2.11% at in the opening 30 minutes of trading Wednesday to change hands at a September low of $164.68 and take their three-day decline past 10.5%.

We've invited Mark Zuckerberg to the European Parliament. Facebook needs to clarify before the representatives of 500 million Europeans that personal data is not being used to manipulate democracy.

— Antonio Tajani (@EP_President) March 20, 2018

Action Alerts Plus holding Facebook lost more than $50 billion in market value Monday and Tuesday, with more than 129.85 million shares changing hands, following revelations that a Cambridge University professor used an app to gather information from 270,000 users and then lied to the company when he then shared that data, as well as information on the volunteers' friends, with a group called Cambridge Analytica, which then allegedly used it on behalf of the 2016 election campaign of President Donald Trump.

U.K. data officials are said to be preparing a search warrant of the Cambridge Analytica offices as early as today, and several U.K. media outlets have reported that the government was angered by the fact that Facebook executives sent their own forensic auditors to the consultancy's office prior to the arrival of British officials.

Democratic Senator Dianne Feinstein, who heads the chamber's Judiciary Committee, also said Tuesday that Zuckerberg should testify before Congress. 

"Fifty million people lost their privacy," she said. "I think that we ought to have the head of Facebook, not their lawyer, not their number two, but their number one, come and state if they're really prepared to lead the industry to some controls that prevent all this from happening."

Facebook is now also the subject of a class action lawsuit filed in Federal Court late Tuesday by the Rosen Law Firm, which alleges that the Menlo Park, Calif.-based group "violated its own purported data privacy policies by allowing third parties to access the personal data of millions of Facebook users without the users' consent" and made "statements were materially false and misleading at all relevant times." 

Backlash against the firm was also evident on Twitter, where WhatsApp founder Brian Acton, who left the group last year to form a charity foundation after selling the company he built with CEO Jan Koum to Facebook for $19 billion, made his feelings on the data scandal public.

It is time. #deletefacebook

— Brian Acton (@brianacton) March 20, 2018

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