Kim Etheredge and Wendi Levy were making hair history for multicultural women across the US with their “Mixed Chicks” hair products. They had put in eight years of hard work to develop and market their product, and were earning an annual revenue of $5 million. But then, Inc.com reports, they discovered the alarmingly similar “Mixed Silk” brand. The Sally Beauty Supply product line for mixed race women came in packages that looked all too familiar. And with its cheaper price tag, the imitation brand threatened to ruin everything the entrepreneurs had  built.

In 2004, Etheredge and Levy debuted “Mixed-Chicks,” a hair solution to the struggles the two dealt with as women of mixed race that they hoped would also help women with similar hair textures. Their product line, which includes shampoo and conditioner, began to sell in salons and beauty-supply stores across the US. In 2009 it even caught the eye of celebrity actress Halle Berry, who named the brand one of the “must-have products” in three national beauty magazines.

That same year, a representative from Sally Beauty Supply approached the two entrepreneurs at a trade show. The woman liked their product and invited the two to speak further about a partnership with Sally Beauty Supply. At first, the opportunity to have Sally Beauty Supply carry their products seemed incredible. But the two did their research and decided that the corporation’s strict return policies weren’t for them.

The duo’s dismissal wasn’t enough to deter Sally’s Beauty Supply. The chain went on to create “Mixed Silk,” and with Sallys’ clerks claiming it was practically the same thing as “Mixed Chicks” except cheaper, the two soon realized that their business was at stake.

Etheredge and Levy found themselves in a difficult situation. If they sued the billion-dollar company, they faced paying $250-500,000 a year in a legal battle that could last for years. In addition if they lost their case, the two risked having to pay Sally’s for lost revenue.

Then again if they won their case, it was a chance to possibility get rid of “Mixed Silk” and collect damages for lost sales and reputation.

“Kim and I felt the same way,” Levy tells Inc.com. “There was no way we could just sit there.”

In March 2011, “Mixed Chicks” formally filed a lawsuit against Sally Beauty Supply for trademark infringement, trade dress infringement and unfair competition claiming that the chain was selling and advertising an imitation of their product.

The co-founders are still locked in a legal battle, and await their May 15 trial date. The lawsuit has cost them big. Although they won’t disclose how much, they’ve had to postpone their plans to take the business international for now. The business has continued to grow in the US, and last year added seven new products and increased its distribution to 3,000 stores.

At the end of the day, the women have no regrets about their decision to sue. As Etheredge says to Inc.com, “You can’t just bully little companies.”