There are two different account billing types in Domotz Pro: Credits type and Subscription type.
The Credit billing system is based on purchasing Domotz credits and then usuing them for activationg or extending the Domotz Agents.
In case of Subscribtions billing type, Domotz will bill automatically every month, using a valid credit card, based on the number of installed Domotz Agents.
To understand which account billing type is associated with your Domotz Pro account, please, log in to portal.domotz.com/portal/account. If in that page you find the payment method section (like shown in the picture below), it means that your account has the Subscription billing type. If the payment method section is not present, it means that your account is using the Domotz Credits.
Please, be careful while reading the following guide, because it contains information for both account billing types.