IATA/ICAO apply only to international transportation, so you are out of luck if you are trying to blame someone other than yourself.
"It codifies the principles and techniques of international air navigation and fosters the planning and development of international
air transport to ensure safe and orderly growth. Its headquarters are located in the
Quartier International of
Montreal,
Quebec,
Canada."
Regarding airport departure display systems, or FIDS (Flight Information Display System) there are many different companies providing this technology and each airport uses their preferred supplier. I'm afraid you will be out of luck here also. Some systems automatically update flight information based on complementing technology such as ACARS, and others require manual update by the airline at the local station. While the station may itself have updated the info, the system displaying the info on airport screens may not update. Therefore, it's simply a blame game. The airport, airline, and information systems will simply blame each other.
It is hard to imagine a scenario where someone could miss a flight at a 4 gate airport. Couldn't you see the aircraft on the tarmac? Could you not have asked someone working one of those gates? If there were a number of people who missed the flight as a result, you might have an argument. However, if you were the only one who missed it, you will not likely get any sympathy from the airline involved.