The Maine Public Utilities Commission Credit: Lori Valigra

PORTLAND, Maine — A class-action lawsuit aims to recoup alleged overbilling of Central Maine Power customers last winter.

The lawsuit filed Thursday adds to the woes for the state’s largest electric utility. CMP already is facing dual investigations over complaints of overbilling, one by the Maine Public Utilities Commission and another by an independent auditor.

Attorney Sumner Lipman said it’s not clear what caused the overcharges but he told reporters that the facts speak for themselves. He said 97,000 customers’ bills increased by 50 percent or more, and another 200,000 saw smaller increases up to 50 percent.

CMP spokeswoman Gail Rice said that under state law the PUC is tasked with ensuring fair, accurate bills, and it has yet to issue its findings. Lipman said his role is to ensure customers are reimbursed.

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