Hello hlubimanci,
please have a first look there: http://helpx.adobe.com/business-catalyst/partner/cancel-paid-site-subscription.html. There you can see the different modalities depending of your arrangement. See e.g.:
After upgrading and launching a site, you can cancel and delete the site at any time. The workflow to delete a site depends on how you paid for the site:
Creative Cloud subscriber >>> Select Site Settings > Site Management, and then click Delete Site.
or
Site administrator - direct billing >>> ...
Hans-Günter