While I'm sympathetic to your feelings, I hope you haven't sent that letter yet, SYL. Dealing in hypotheticals, i.e. deaf grannies, won't get you anywhere. Your complaint will be given much more attention if you deal with specifics, who, what and where, as they pertained to you.

I'm pretty sure many of us missed a flight in similar circumstances, but usually that it is one lesson, few of us need to have repeated lol.