If you own a Fitbit and have been trusting its sleep data, you might want to listen up. A new class action lawsuit filed against the company says it can’t track sleep at all, alleging it’s some sort of modern day snake oil.

“This, plainly, is false,” the suit says, according to The Recorder. “The Fitbit sleep-tracking function simply does not and cannot inform the user how well they slept with any accuracy whatsoever.”

Accuracy is the primary pain point. The class action suit claims Fitbit suggests users sleep up to 67 more minutes per night than they actually do, because the sensors aren’t as accurate as other options. For someone who is trying to improve sleep, and sleep more, learning that you’ve slept an hour more than you actually did is pretty useless data.

“Thinking you are sleeping up to 67 minutes more than you actually are can obviously cause health consequences, especially over the long term,” the suit says.

Fitbit hasn’t responded to the lawsuit, but it’s the latest ding against a company that has struggled with class action lawsuits in the past. Just over a year ago, for example, company was sued after the Fitbit Force caused skin irritations.