Contact
Two channels are published: one email address for anything written, and a Discord server for questions in the open.
Where to write
One email address covers enquiries, complaints, data protection questions and security reports. No postal address and no telephone number has been published for the operator.
There is no contact form on this site. Nothing you type anywhere on it is sent anywhere, which is what the privacy notice already states.
Data protection requests
Requests about your personal data have a page of their own: How to exercise your data protection rights
That page describes what to put in a request: the right you are exercising, its scope, and a reply address. A request goes to the same address as everything else.
Complaints and authorities
The terms set out the route. Send a complaint to the operator first, using the contact address in the section above.
If you are a consumer and the complaint is not settled, out of court resolution of consumer disputes in the Czech Republic is run by the Czech Trade Inspection Authority (Česká obchodní inspekce). Its address is itself an open item on this site.
For personal data, the supervisory authority is the Office for Personal Data Protection (Úřad pro ochranu osobních údajů). You may also complain in the country where you live or work, or where you think an infringement happened, and you may seek a judicial remedy. Read the privacy notice