I achieved my quickest, simplest, most pleasant customer service interaction yet with an airline by writing a letter explaining what they did (with transaction IDs, confirmation numbers, etc), and what they should have done. The situation was not entirely simple, and I was not looking forward to explaining it verbally to a rep.

They sent me back a simple letter a couple weeks later saying they'd resolved the issue the way I requested and provided me the updated documentation.

I'll definitely consider this approach next time something like this happens.

I keep this article in my bookmarks re: how to write a proper complaint letter. It talks specifically about credit reporting agencies, but a lot of what he says can be applied anywhere else: https://www.kalzumeus.com/2017/09/09/identity-theft-credit-r...