Oh, then its a snafu on your part. You're supposed to leave a info@domainname.fi/com/whatever e-mail for registrations and save your personal e-mail for personal stuff. Of course if you register with your personal e-mail you're going to get bombed with all sorts of trash!
At the time I started my firm, 8 years ago, I didn't have a domain. When the authorities asked for my e-mail address, I gave them one that was most likely to stand time, not the "bizman##@provider.com" I use for less formal correspondence. Actually the address in their database got outdated, but I updated the information. The address in question is "my.company@myISP.fi", so actually it's not that personal... I suppose my domain contract includes some kind of e-mail services, too, so changing the information in the official database could be an option. On the other hand, that would add one mailbox more to follow. I also guess that my ISP is doing a better job in filtering trash than my server hosting service would do.