A federal judge in Oakland is asking Postmates Inc. to explain why the company should not be held in contempt for violating her order compelling the company to arbitrate more than 5,000 worker misclassification cases brought on behalf of individual couriers.

U.S. District Judge Saundra Brown Armstrong of the Northern District of California issued a show cause order Tuesday after the couriers’ lawyers at Keller Lenkner asked her last week to hold the company in contempt. Postmates, they wrote, failed to pay its portion of the filing fees in the 5,257 cases brought on behalf of couriers at the American Arbitration Association, resulting in AAA administratively closing the cases.