CHICAGO (CBS) — ComEd faces a new class action lawsuit claiming it violated the Illinois Consumer Fraud Act and should reimburse customers who were overcharged for electricity as part of a yearslong bribery scheme the company has admitted to.

The lawsuit comes more than a week after federal prosecutors announced ComEd had been charged with a years-long bribery scheme involving the company’s arrangement for jobs, contracts, and payments to allies and associates of Illinois House Speaker Michael Madigan.

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The lawsuit was filed Monday in Cook County Circuit Court by Randall Kuhn of Lake Forest, Robert Neiman of Glencoe, Erica Lieschke of Chicago, and Chicago-based Windward Roofing Construction; all ComEd customers since 2011, when prosecutors say the scheme began.

“Through rampant and widespread corruption in the form of bribery of Illinois elected officials, ComEd and its parent company, Exelon Corporation, deprived ratepayers of vast sums of money, totaling in the hundreds of millions, if not billions, of dollars,” the lawsuit states.

As part of a deferred prosecution agreement, the company admitted attempting to influence legislation regarding the regulatory process that determines the rates it is allowed to charge customers for electricity. Prosecutors estimated the company benefited by $150 million from that legislation.

Madigan, 78, has not been charged with a crime, and a spokeswoman has said he “has never made a legislative decision with improper motives and has engaged in no wrongdoing here. Any claim to the contrary is unfounded.”

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ComEd agreed to pay a $200 million fine, and prosecutors agreed to defer prosecution of the company for three years while it cooperates with the federal investigation. Charges will be dropped after three years if ComEd complies with its obligations.

However, the lawsuit filed against ComEd on Monday claims the agreement with federal prosecutors does nothing to reimburse customers who were overcharged as a result of the bribery scheme.

The lawsuit seeks class action status on behalf of all ComEd customers who paid utility bills that included subsidies and rate increases since 2011. The filing estimates the class would include millions of individuals and businesses who are direct and indirect ComEd customers.

ComEd and its parent company, Exelon, has said the utility has fully cooperated with federal prosecutors since the beginning of the investigation, and has “taken extensive remedial measures” to reform its lobbying practices.

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“We are committed to maintaining the highest standards of integrity and ethical behavior. In the past, some of ComEd’s lobbying practices and interactions with public officials did not live up to that commitment.  When we learned about the inappropriate conduct, we acted swiftly to investigate,” Exelon CEO Christopher M. Crane said in a statement earlier this month. “We concluded from the investigation that a small number of senior ComEd employees and outside contractors orchestrated this misconduct, and they no longer work for the company. Since then, we have taken robust action to aggressively identify and address deficiencies, including enhancing our compliance governance and our lobbying policies to prevent this type of conduct. We apologize for the past conduct that didn’t live up to our own values, and we will ensure this cannot happen again.”