The hibernation plan allows you to keep all your data (contacts, workflows, reports) for 9.99 USD or EUR (VAT not included) per month, depending on the currency of your account.
However, all credit-consuming and data-modifying actions are disabled, which means that all workflows are set on Pause and you can't add new contacts to your database.
To hibernate your subscription:
Navigate to Settings > Subscription.
Click on the Cancel button.
Select the Hibernation mode option.