John and Roman Cresto made millions of dollars selling themselves as e-commerce “experts” who could teach regular consumers and investors the secret to selling success on Amazon and Walmart, for a price.

They splashed lavish vacations and high-end cars across their social media account, creating a multimillion-dollar image of success that federal regulators now say was fueled by falsehoods and deception.

The case is the latest example of the Federal Trade Commission cracking down on deceptive e-commerce consultancies that target consumers and fledgling online businesses. A robust industry of consultants and agencies, often referred to as “coaches” or “gurus,” have emerged as retailers increasingly move online and marketplaces on sites such as Amazon and Walmart flourish.