Sarah Tew/CNET

T-Mobile, known for bashing its competitors in the wireless business, is in hot water for the treatment of its own employees.

One of the nation's largest wireless carriers violated federal labor laws by illegally restricting employees from discussing basic workplace issues like wages and suppressing their attempts to organize, according to Christine Dibble, an administrative law judge for the National Labor Relations Board, an independent federal agency created to enforce labor laws.

The ruling on Wednesday caps the Communications Workers of America's long-standing dispute with T-Mobile and its majority shareholder, Deutsche Telekom, over the rights of workers to organize. The CWA has been pushing for T-Mobile's employees to join its union, which already represents employees at Verizon and AT&T.

"This decision exposes the deliberate campaign by T-Mobile US management to break the law systematically and on a nationwide scale, blocking workers from exercising their right to organize and bargain collectively," Larry Cohen, president of the CWA, said in a statement.

At issue are restrictive e-mail policies and a confidentiality agreement found in the company's employee handbook, which prevented workers from talking with one another and with the media. Dibble ruled that the policies were illegal and ordered T-Mobile to post a notice to the staff reaffirming their rights to form or assist a union and listing policies that T-Mobile is not allowed to enforce

The decision is a possible black eye for T-Mobile, which has built up an image of a fun, rebellious carrier thanks to charismatic CEO John Legere and his "Uncarrier" campaign. As part of its Uncarrier push, Legere unveiled two new programs on Wednesday: a move to offer simplified pricing plans to businesses and an offer to buy out the device cost for any customer looking to switch over.

T-Mobile downplayed the judge's decision.

"This is simply a ruling about a technical issue in the law that relates to policies that are common to companies across the country," a T-Mobile spokesperson said. "There are no allegations that any employee has been impacted by these policies."