Last June, the U.S. Supreme Court ruled in Janus v. AFSCME that requiring public sector employees to pay mandatory union fees violates their First Amendment rights.

But unions in Washington, Oregon and California are continuing to do it anyway, according to the Freedom Foundation, a nonprofit legal firm representing public employees attempting to cut ties with their unions in all three states.

MORE NEWS: Know These Before Moving From Cyprus To The UK

On Monday, special needs teacher Bethany Mendez joined with four other public school educators to file a federal class action lawsuit against the California Teachers Association over the continued paycheck deductions. The Fremont, California teacher notified her union that she resigned and revoked authorization for dues deductions from her paycheck in October, but the union has refused to let her go and continues to dock her pay, The Washington Times reports.

Mendez and other educators who want to leave instead received a letter from the CTA informing them they can only withdraw from the union during a specific 30-day window each year, described as “not less than thirty (30) days and not more than sixty (60) days before the annual anniversary date” of an employee’s most recent recommitment.

Mendez explained that the CTA launched a recommitment drive in the weeks leading up to the Janus Supreme Court decision, and teachers did not understand the reasons why they were being pressured to sign until it was too late.

“They pushed these recommitments knowing full well that the passing of Janus may occur, but the employees were never informed of this,” Mendez said. “So I signed, believing there were no other options available to me and that the deductions would be made regardless. These commitment cards have locked employees into funding the union.”

The recommitment cards and annual exit window are tactics unions have perfected to stem the exodus of members in states that have freed workers from paying dues as a condition of employment. In Michigan, Wisconsin and other states, educators left their state unions in droves when given the option, fueling a national trend that’s undermining Big Labor’s main moneymaker.

“The percentage of public school teachers who belong to unions has been declining steadily for years, even before Janus,” the Times notes. “About 70 percent were union members in the 2016-16 National Teacher and Principal Survey, down from 74 percent in 2011-12, according to Education Week.”

MORE NEWS: How to prepare for face-to-face classes

“Unions are unjustly enriched and benefit themselves at the expense of plaintiffs by retaining the dues over the objections and without the consent of the plaintiffs,” Freedom Foundation attorney Harmett K. Dhillon told the news site.

The California lawsuit names the California Teachers Association, California Attorney General Xavier Becerra, the National Education Association and five local unions and superintendents, the Times reports.

“What we’re looking for is really more options for teachers, but most importantly, that No. 1, that the state comply with the Constitution,” Dhillon said. “And the state is involved here because the state makes the unions the exclusive representative, and there is no competition in that system.”

Mendez and four other public school teachers decided to sue both for financial and political reasons, Dhillon said. The Fremont Unified District Teachers Association, for example, charges $1,500 per year in dues. In 2016, its parent union, the NEA, spent more than $30 million on politics, virtually all of it on Democrats and liberal causes.

“The unions use the plaintiff’s dues deductions to promote many political positions with which the plaintiffs in our lawsuit do not agree,” Dhillon said.