How to handle accounts?

How to handle accounts?

Hello,

I'm client of zoho one and I have zoho mail account who I use for reselling to my client zoho mail. 
In zoho one it's included a big space for email and  I can't use because my support email it's in email workspace.

How can I use zoho one for support@mydomain.com and handle zoho email workplace? 

Is there another way to manage reseller email in zoho?

Thank you