Less than a week after Walmart (WMT) said it would close a handful of locations and lay off more than 2,000 employees, the retailer is now fending off accusations from disgruntled workers who say they were being unfairly punished for protesting the company’s employee practices.

Citing prolonged plumbing issues at five stores in California, Texas, Oklahoma and Florida, Walmart told employees it had no choice but to close. Repairs could take up to six months or longer, according to Walmart.

“We understand this decision has been difficult on our associates and our customers and we aim to reopen these stores as soon as these issues are resolved and improvements are made,” Walmart said in a statement provided to Yahoo Finance.

But members of Our Walmart, an activist group that pushes for better wages and benefits for workers, aren’t buying the excuse. In an injunction filed Sunday by The United Food and Commercial Workers International Union — of which Our Walmart is a branch — they claim Walmart's real motive was to shut down one store specifically: its Pico Rivera, Calif., location. The store was the site of the first worker protest against the company’s employee practices in 2012, which helped incite the minimum wage debate that’s taken hold across the country. The union, which filed the charge through the National Labor Review Board, the federal agency that enforces labor laws, wants to force Walmart to rehire all 2,200 workers affected.

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View photos Pico Rivera workers protest their store closing last week. Source: Our Walmart More

With the Pico Rivera store’s closing, more than 500 employees were laid off, including Venanzia Luna, a 36-year-old deli manager who has worked at the location for eight years.

“This has nothing to do with plumbing,” Luna told Yahoo Finance. “They wanted to get rid of us one way or the other.”

Luna was among the first workers to walk out of the store in protest 2012 and was an active participant in future protests. Their latest effort, in which dozens of protesters blocked off an intersection in front of the store last fall, resulted in her arrest as well as others. Their actions have been mimicked across the country, inspiring part-time wage earners from fast food companies like McDonald’s and Burger King to follow suit.

A Walmart spokesperson denied these claims in a statement provided to Yahoo Finance:

“We don't believe there is any basis for an injunction. As we have said all along, these stores were closed temporarily so we could fix the ongoing plumbing issues and it would be unfortunate if this outside group attempts to slow this process down for our associates and customers. Each of these five locations had more than 100 plumbing problems reported over the last two years, the most out of our more than 5,000 stores in the U.S.”

After enduring three years of nationwide protests, media scrutiny and criticism from politicians and business groups, Walmart announced it would give 40% of its workforce — half a million employees – raises by June 2015. With the changes, the company's average full-time worker would earn $13 an hour, up from $12.85. Part-time workers will be bumped from $9.48 an hour to $10.

Luna, who earns $14.40 as a manager, says she was expecting to be bumped up to $15 by June. As required by law, Walmart will be offering two months’ pay to employees who were laid off and human resource staffers will work to transfer employees to other store locations. But Luna has no plans to sign the forms that would guarantee her severance pay — by signing, she would forfeit the right to sue the company or hold any future protests on site.

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