Information about the domain owner can never be empty, and each domain must have contact with the information about its owner. If the data is open, then it can be viewed through the WHOIS network protocol — either directly through the application on the PC, or through online services, for example — dig.ua.
In WHOIS, the domain owner will have the name "Registrant". This is how the WHOIS query for the domain "NIC.UA" looks like:
Here you can see the contact information of the domain owner, and thus you can easily contact him.
But what if the data is hidden or not displayed? If the domain is registered on NIC.UA, then you can send a message to the owner via special form.
Please note: NIC.UA does not guarantee a response to your request. We are only a link between you and the domain owner.