Again, slightly off the specific topic. But, as others have mentioned, it's always best to make written complaints: a) as concise as possible; b) as accurate as possible; c) as unemotional as possible; and d) ending with what you actually want by way of recompense or action. If you can manage to be a touch light-hearted (without sarcasm!) than may help too. Though it's sometimes difficult to believe from the responses you get, you are writing to regular human beings in the "Customer Relations" department...
A story from nearly 20 years ago, flying from JFK to LHR on BA.......... to cut a very long story short, the flight took over 24 hours, via Montreal! Now, not everything that went wrong was directly in BA's control- but their handling of the various delays, calamities, misunderstanding, false starts and stops was lamentable at every level. By chance, I had as reading material a copy of the Harvard Business Review - in which there was an article by Colin Marshall called (something like): "BA's 7 Golden Rules of Customer Service". Well, that night, BA did the precise, diametric opposite of each of the 7, with great relish.
So I wrote to Sir Colin himself, pointing out (on a single page) that he really should run off a few copies of his excellent thoughts and actually give them to his staff.... He wrote back - the man himself - saying, "It's a fair cop!" and asking me to call his office to get a free ticket for my trouble......
AGB