Many men and women in the National Guard and Reserve are returning home from fighting in Iraq and Afghanistan to an unwelcomed surprise -- they've been demoted, or even replaced, at work.

While the law called Uniformed Services Employment and Reemployment Rights Act is supposed to ensure that employers must take military members back at their same pay and position after they return from service, many are not following it.

"60 Minutes" reported that according to the Pentagon, more than 10 percent of guardsmen and reservists have problems returning to work when they come back from deployment.

According to The Washington Post, even more incidents go unreported. In a 2007 article, the newspaper said that according to the Government Accountability Office, more than 16,000 complaints were filed between 2004 and 2006. The GAO estimated that fewer than 30 percent of reservists who experienced a violation actually filed a complaint.

The reason for the small number of official complaints, the Washington Post reported, is that servicemen and women have problems proving employers wrongly terminated their jobs. According to the newspaper, the burden is on the servicemen and women to prove that they lost their jobs as a result of their military service and for no other reason.

Some of the companies that have had complaints filed against them include Wal-Mart, American Airlines and UPS, "60 Minutes" reported.

Even military-focused institutions have violated the law.

According to "60 Minutes," one of the employers who didn't follow the USERRA law was the VA Medical Center in Augusta, Ga. According to Lesley Stahl's report, Army Reservist Joanne Merritt returned home from a two-year deployment to discover she'd lost her job as a nurse who worked with wounded soldiers.

Merritt told "60 Minutes" that the VA Medical Center explained to her that she was gone too long so they "had to give that (job) to somebody else."

According to "60 Minutes," Merritt filed a complaint against the VA and was able to get her job back within a couple of weeks.

But why are companies violating the law?

Dave Miller, the vice president of Con-way freight, told "60 Minutes" that despite pledging to support his guard and reserve employees, he is losing his patience. According to Miller, the deployments are long, employees are being called up for multiple tours of duty, they're called up on short notice, and it's costly for companies to hire and train temporary replacements.

For veterans who have experienced violations to the USERRA, Assistant Secretary of Defense Thomas Hall told "60 Minutes" he vows to offer help.

"Let me make this commitment right on the air, if I could just for a moment. If there's any guardsman or reservist or family member that has a problem, call my office. Call me personally," Hall told Stahl on "60 Minutes." "My number is 703-697-6631. And I will ensure that I put a case worker on it. If necessary, I will call the head of the company or the agency personally. I don't just make that offer just precipitously. I mean that because we're concerned about it. My office will react, and I invite people, if they have a problem, tell me."