Email hello@feriday.com.
Please include the country, the state or region, the year, and a link to the official source (gazette notice, ministry circular). Corrections go into a hand-maintained override file that always takes priority over generated data, so a good report gets fixed quickly.
We add countries deliberately rather than publishing every country at once, so that each page is actually useful. Tell us which country and region you need and it goes on the list.