American Express will reimburse $85 million to about 250,000 customers to resolve accusations that the company violated federal law in its marketing, billing and debt collection practices, the company and the government said Monday.

The settlement is the latest in a series of enforcement actions that federal and state regulators have brought against some of the nation’s largest financial institutions for problems in their credit card businesses. In each of the cases, regulators have exposed critical flaws in how the banks monitor vendors that perform central business functions.

The multiagency investigation of American Express included the Consumer Financial Protection Bureau, the Federal Reserve, the Office of the Comptroller of the Currency and the Utah Department of Financial Institutions. They discovered violations of consumer protection laws between 2003 and this year that started “from the moment a consumer shopped for a card to the moment the consumer got a phone call about long overdue debt,” Richard Cordray, the director of the consumer protection bureau, said in a statement.

To win customers for its Blue Sky travel reward credit card program, the lender sometimes offered customers a misleading promotion. Some customers thought they would receive a $300 reward, but that never materialized, the regulators said.