Have Mail Lite, wish to add/purchase 2nd domain and use email

Have Mail Lite, wish to add/purchase 2nd domain and use email

Hello,
I have recently created two new businesses.  I have successfully used Zoho to create a domain for one business and have set up two email addresses / users on that domain.  I am trying to figure out how to create a second domain, just like I did the first one, and create email addresses for that one as well.   When I go to but a new domain in settings I get "you have reached the maximum number of domain purchase limit".  I have emailed support but they have been unresponsive.  Help please!