The Federal Trade Commission sued Amazon on Wednesday, alleging that the e-commerce giant has tricked millions of consumers into signing up for its Amazon Prime subscription service through deceptive user interface designs.

The complaint filed in the US District Court for the Western District of Washington also takes aim at Amazon for allegedly trying to keep users subscribed who wished to cancel their memberships.

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“Specifically, Amazon used manipulative, coercive, or deceptive user-interface designs known as “dark patterns” to trick consumers into enrolling in automatically-renewing Prime subscriptions,” the FTC complaint said.

Amazon did not immediately respond to a request for comment.