I've received similar emails or letters from PMCO about various issues over the past 10 years. What I do is resend the complaint by snail mail with a copy of the original complaint and response. I will typically add language such as "i am disappointed in the quality of your reply which does not even address my issue and appear to be a boilerplate response." Once this is sent, the letter was addressed to my satisfaction.

I am certainly no apologist for United or Continental, but I have had similar initial responses by other corporations to complaints over the years.