(putting on my airline executive hat)

The *worst* thing for the airline (and BEST for you) is to go thru the U.S. DOT Consumer Protection group as this can fall under fraudulent pricing
(i kid you not, this happened at another airline and I had to handle it after an agent made an error in a reservation, and it too, was "fixed" at check-in.. customer complained, then i get a nasty gram from DOT along with a copy of the laws regarding pricing)

http://airconsumer.dot.gov/CP_AirlineService.htm

this gets recorded AND MARKED... and it goes to a different level of customer relations folks (outside the zombies paid $9/hour that just do auto-replies "screw you").