Activating spam-proof official company email@example.com email for your company is possible through the government portal eesti.ee. Unicount hopes that it will become easier with the new version of eesti.ee under construction for entrepreneurs.
Log in to eesti.ee old version with your e-resident card or Smart-ID
Navigate to My Data>Settings>Official e-mail.
Here you can set up forwarding addresses for your personal and company official eesti.ee email aliases.
Both "personal IDfirstname.lastname@example.org" and company "email@example.com" reject all mail from non-government IP addresses not authorized by the Estonian State Information Systems Authority.
Now you can now go to e-Business Register and use your "firstname.lastname@example.org" forwarding alias as your official publicly visible company email. This enables you to receive all official communication to your personal email address while all unsolicited spam emails get rejected. Here is the manual for changing the company's public email.