A union that represents communications workers across the U.S. on Monday said that so far this year more than 2,000 current and former employees at a General Dynamics’ [GD] business have complained to the Department of Labor about wage violations at federal call centers run by the company.

The Communications Workers of America said that workers at five federal contract call centers filed new wage theft complaints this week. The allegations include underpayment and misclassification of workers by GD’s Information Technology business.

“These complaints provide further evidence that thousands of workers at a majority of GDIT call centers across the nation are systematically underpaid,” Chris Shelton, president of the CWA, said in a statement. “That’s why we are calling on the Department of Labor to conduct an enterprise-wide investigation at GDIT.”

GD pointed out that the CWA doesn’t represent its employees and that the government conducts the company’s adherence to labor laws.

In its own statement, GDIT said that it “values our people and the work that they perform. The company takes seriously our obligations under the Fair Labor Standards Act and Service Contract Act. Our call center employees are not represented by the Communications Workers of America. Similar to other federal contractors, the company is subject to routine compliance reviews and as with any notice received it will engage with the relevant parties including our employees and the Department of Labor.”

The CWA said that GDIT has about 10,000 employees at 11 federal call centers under a contract with the Centers for Medicare and Medicaid Services. The union claims that GDIT, and Vangent, which GD acquired in 2011, “have a history of wage theft, saying that “Since 2007, the companies have agreed to pay their workers $4.2 million in back wages based on Wage and Hour Division investigations.” The Wage and Hour Division is part of the Labor Department.