First: I removed the line about Danzig being taken from Prussia Germany and given to Poland. If it was a free city it was not part of Poland.
Second: What were they complaining about? - "Many complaints by Danzigers to the League of Nations for 20 years were completely ignored." --rmhermen
Several functions , like collecting customs, postal deliveries etc were 'given' to Poland, who tried to 'Polonionize' everything.
While Danzig was called a free state , it was in reality not free anymore.
H. Jonat