Didn't feel like waiting another 15 minutes on hold with no assurance it would be successful. Complained to DoT, submitted complaint to LH through their system, and in a week or so I'll charge back whatever is not refunded on the credit card. None of those options are very time consuming, and I suspect at least one of them will work. Bonus points if LH double refunds (e.g., I get the chargeback and then 6 weeks later when they decide to get around to the complaint, they refund based on the complaint) because of their poor experience design.