A total of 15,867 Amazon Flex drivers across three states have filed arbitration with the American Arbitration Association (AAA) this week, alleging Amazon had misclassified their job roles as independent contractors rather than employees, resulting in underpaid and lost wages.

Thousands of Amazon Flex drivers in the US have initiated arbitration claims against e-commerce giant Amazon, alleging that they have been misclassified as independent contractors instead of employees, Reuters has reported, citing lawyers representing the drivers.

Two law firms spearheading the action said about 15,860 Amazon Flex drivers have submitted arbitration claims with the American Arbitration Association, where 453 similar cases are already being litigated. Amazon’s Flex program, which was founded in 2015, signs up drivers to deliver packages with their own cars and a special app.