I receive every e-mail TWICE !

I assume you mean email from Stardock. At the bottom of every email from Stardock I believe there's an unsubscribe option. Have you tried that?

You can also look here: https://support.stardock.com/space/SHC/15695874/How+do+I+unsubscribe+from+Stardock+emails%3F

It is twice the SAME email-address !!!

I'm afraid I won't receive any more emails then!?

Use the account management option in the link I posted:

https://www.stardock.com/accounts/subscriptions

Or you can submit a ticket to Stardock Support describing your problem here:

https://stardock.atlassian.net/servicedesk/customer/portal/4/group/14/create/10139

Make note of your ticket number, and wait for their reply. Just submit once.