Southwest Airlines has been sued by a passenger who said it failed to provide refunds to passengers left stranded when an operational meltdown led the carrier to cancel more than 15,000 flights late last month.

In a proposed class action filed on Dec. 30 in New Orleans federal court, Eric Capdeville accused Southwest of breach of contract after a fierce winter storm that swept across the US shortly before Christmas upended the carrier’s schedule.

Though Southwest has promised to reimburse passengers for expenses, Capdeville said it offered only a credit to him and his daughter after scrapping their Dec. 27 flight to Portland, Ore., from New Orleans and being unable to book alternative travel.

Affected passengers “cannot use their airline tickets through no fault of their own and they are not getting the benefit of their bargain with defendant,” the complaint said.

Capdeville, a Marrero, Louisiana resident, is seeking damages for passengers on Southwest flights canceled since Dec. 24, and who did not receive refunds or expense reimbursements.

In a statement on Tuesday, Southwest had no comment on the lawsuit, but said it had “several high priority efforts underway to do right by our customers, including processing refunds from canceled flights, and reimbursing customers for expenses incurred as a result of the irregular operations.”

Capdeville’s lawyer did not immediately respond to requests for additional comment.

The meltdown at Dallas-based Southwest has been blamed on staffing shortages and outdated flight scheduling software.

Southwest has said it would reimburse affected passengers for reasonable expenses such as last-minute hotel, rental car and dining costs, but it might take several weeks.

The carrier largely restored normal operations on Dec. 30, several days after other airlines had recovered from the storm.

In a Dec. 29 letter to Southwest Chief Executive Bob Jordan, Transportation Secretary Pete Buttigieg called the disruptions “unacceptable” and said the law requires refunds when carriers cancel flights unless passengers accept rebooking.