A federal investigation spelled bad news for consumers and Discover alike when it determined the bank had duped people into signing up for payment protection plans and other add-on services they probably didn't need.

The Consumer Financial Protection Bureau and Federal Deposit Insurance Corp. have ordered Discover to cough up $200 million in refunds to more than 3.5 million customers.

The alleged deception was carried out between December 2007 and August 2011, and the services cost about $3 to $10 a month.

"The FDIC and CFPB have determined that Discover has engaged in deceptive acts and practices in or affecting commerce," said the government filing. "The FDIC further has determined that Discover has engaged in unsafe or unsound banking practices."