The workers filed a lawsuit in South Carolina state court against Starbucks and the manager at the store in Anderson, a few miles from Clemson University.
They claimed the manager urged police to charge them with assault and kidnapping after the workers pressed her for a raise in August.
At least 240 other Starbucks in the United States have unionized over the past year, and the company has been accused of illegal labor practices at dozens of locations.
According to the complaint, the Anderson workers on Aug. 1 presented the manager with a letter calling for a raise.
She then called a Starbucks district manager and falsely claimed the workers were preventing her from leaving the store, the plaintiffs claim.
Starbucks released a statement on Aug. 8 saying the manager had felt unsafe and the workers were suspended with pay pending an investigation.
The workers accused Starbucks of defamation and abusing the legal process in violation of state law. »