Uber Technologies Inc. (UBER) shares took a hit Monday as federal regulators turned up the heat on the company's subscription business.

The Federal Trade Commission, joined by 21 states and Washington, D.C., filed an amended complaint accusing Uber of some pretty aggressive tactics with its Uber One subscription service. The allegations? Enrolling customers without their consent, failing to deliver the perks it promised—like $0 delivery fees—and making it ridiculously hard to cancel.

This isn't the FTC's first swing at Uber. The agency initially sued the company back in April over deceptive billing practices tied to Uber One. Now regulators are expanding their case and seeking civil penalties under the Restore Online Shoppers' Confidence Act and various state consumer protection laws.

Here's what regulators say went wrong: Uber markets Uber One as a money-saver, promising up to $25 in monthly savings and free delivery. But many users report they were still hit with fees or never saw those advertised discounts materialize.

Even worse, according to the complaint, some customers were signed up without ever agreeing to it. Free-trial users allegedly got rolled into paid plans and billed before their trials even ended. Others say they were charged for Uber One despite never intentionally enrolling in the first place.

And if you want out? Good luck. The complaint alleges that canceling Uber One can require navigating 23 screens and completing up to 32 separate actions. That's quite a process for a service Uber claims you can "cancel anytime."

Uber shares were down 4.34% at $81.42 at the time of publication on Monday.