A Southwest Airlines passenger filed a complaint against the airline for allegedly failing to refund passengers after the airline canceled more than 15,000 flights during the holiday season. Eric Capdeville filed the proposed class action in a federal Louisiana court on Friday. Capdeville accused Southwest Airlines of breach of contract and seeks to recover damages for passengers affected by cancellations from December 24 that did not receive refunds or reimbursements.

Capdeville purchased tickets for himself and his daughter to fly from New Orleans, Louisiana to Portland, Oregon on December 27. The flight was cancelled shortly before departure and he was forced to forfeit his nonrefundable hotel in Portland. Instead of providing a refund or alternative flight, the airline offered “a credit for use on a future flight.” Capdeville argued the airline’s failure to provide refunds or alternatives affected passengers who “cannot use their airline tickets through no fault of their own.”

The US Department of Transportation (DOT) stated that customers who purchased flight tickets are entitled to a refund in the event of a cancellation or “significant delays.” Section nine of Southwest’s contract of carriage requires the company to either “transport the passenger at no additional charge on the carrier’s next flight,” or “refund the unused portion of the passenger’s fare.”

Southwest Airlines, one of the largest low-cost domestic carriers in the country, faced significant disruptions to its operating systems following an unprecedented winter storm that saw record-low temperatures and substantial snowfall across the US. According to the tracking database Flightradar24, the airline cancelled more than 60% of their scheduled flights for December 28 and 29.

Southwest Airlines CEO Bob Jordan apologized for the disruptions and promised to reimburse affected passengers for additional expenses incurred in a video posted to the company’s Twitter. The DOT announced its plans to investigate whether the mass cancellations were “controllable and if Southwest is complying with its customer service plan.”