Philadelphia-based cable giant Comcast is being sued by the state of Washington on grounds that it deceptively enrolled hundreds of thousands of customers in a service protection plan they never agreed to joining.

The $100 million suit, originally filed last summer, was vastly expanded last week after Washington Attorney General Bob Ferguson amended it present new evidence of Comcast's alleged violation of the state Consumer Protection Act.

Prosecutors say Comcast misrepresented the scope and cost of its Service Protection Plan, a program designed to reduce the cost of repairs, and exploited more than half a million Washingtonians from 2011 to 2015.

A sample of recorded calls between SPP subscribers and Comcast representatives allegedly revealed the company may have enrolled more than half of its Washington customers without their consent.

In some cases, customers were told SPP was free of charge, but Comcast billed them a monthly fee of $6 after the first month. Even customers who explicitly declined the plan wound up getting enrolled. Subscriptions to the plan during the period covered by the lawsuit amounted to $73 million, according to the Attorney General.

The investigation further revealed that while customers were allegedly told the "comprehensive" plan would reduce the cost of repairs, the SPP does not call indoor and out wall wiring, which makes up the majority of its service. In effect, SPP covered the cost of a technician pointing what customers most likely already knew: their equipment was defective or broken.

New evidence presented in the Attorney General's amended lawsuit comes after Comcast admitted deleted phone recordings it had been ordered to preserve for the state's investigation.

“This new evidence makes clear that Comcast’s conduct is even more egregious than we first realized,” Ferguson said. “The extent of their deception is shocking, and I will hold them accountable for their treatment of Washington consumers.”

Comcast, in a statement obtained by Engadget, denied wrongdoing and claimed that the Service Protection Plan covered nearly all charges related to repairs.