A FlyerTalk Posting Legend
Join Date: Sep 2002
Location: LAX/TPE
Programs: United 1K, JAL Sapphire, SPG Lifetime Platinum, National Executive Elite, Hertz PC, Avis PC
Posts: 47,214
Are you based in the USA?
1. file a DOT complaint, document and complaint and any response
2. prepare to file a small claims lawsuit, usually $50 to file plus any fees for service of process
Did you attempt to resolve this at the airport? Via social media or chat? Prepare to document your attempts to reach United to fix the problem along with United's failure to respond - this may be asked in court.
This honestly should have been dealt with back in Jan-Feb with a credit card dispute, but DOT+small claims may be your best option now