Webhosting can be terminated through the cancellation form accessible after login to the customer account where the service is registered. After login at https://admin.forpsi.com/
choose in the left menu the link "Webhosting", click on its name and in the new opened window choose link "service cancellation".
The domain will be automatically cancelled if it isn´t renewed and paid for next period. After its expiration date and the expiry of its protection period, it will be released for a new registration. Notices about the impending expiration will be sent to the contact email of the domain owner. If you are not interested in the domain renewal, just don´t react on it.