When Rihanna started a lingerie collection in 2018, she teamed up with the start-up behind Kate Hudson’s athleisure line Fabletics.

But Fabletics and the start-up, TechStyle Fashion Group, faced complaints about deceptive billing tactics and now Rihanna’s line, Savage x Fenty, which has been praised for using models of different body types and ethnicities in its marketing, is facing some of the same criticism.

On Tuesday, Truth in Advertising, a nonprofit organization, said that Savage x Fenty “ensnares consumers into unwanted monthly charges,” through a membership plan that was difficult to opt out of. It said it had alerted the Federal Trade Commission to the line’s business practices, which it believes violate the agency’s rules and the Restore Online Shoppers’ Confidence Act.

When consumers buy items like bras and underwear from the Savage x Fenty website, the brand allegedly enrolls consumers into $50 monthly subscriptions “without disclosing all the material terms and conditions of the offer,” Truth in Advertising said. The prices that appear when an item is added to a shopper’s online cart — say, $19.50 for a pair of leggings — require a membership. For nonmembers, the price of the leggings can be more than double. Truth in Advertising added that the brand also used “dissuasion and diversion tactics” when consumers tried to cancel memberships.