There is no Add User button

There is no Add User button

Hello. I am using Zoho Mail as an extension of Zoho One. The problem is, I cannot create new e-mail addresses, because there is no Add User button. I'm attaching a screenshot of it. Any help would be great. Thank you.

Note: If I only can add a user as a Zoho One employee, with paying $35 more, it is just unfair. I just want to add some e-mail addresses for specific purposes, like info@... accounting@... or abc.department@.... ; not to add employees. And no, I don't want to create aliasses. I need completely seperated mailboxes for security and privacy concerns.