To cancel your subscription, you need to first delete all you Domotz Collectors from the Domotz Portal. If you delete all your Domotz Collectors.
To remove the Domotz Collector licenses, Domotz sites, or Domotz Agents you might access the Portal (https://portal.domotz.com), go to the Subscriptions tab, click on Edit:
and then Delete the Domotz Agent you want to.
Once the subscription is deleted your upcoming invoice will be updated to reflect the changes you just made to your account subscriptions.