How to close only my CRM Account

I set up our company's Zoho Mail and later clicked on the CRM to check it out. I was automatically signed up for the Enterprise Free Trial as as a Super Admin. Later, a college, who has a mail account under our zoho organization also clicked on the CRM to check it out and it signed him up automatically for a separate Enterprise Free Trial. When he invited me to his CRM Organization it tells me that I can not join it because I'm the only active member of another CRM organization, but when I try to delete myself from the current CRM Organization that I'm a part of, I can't because I'm the super admin and only user.

Help would be appreciated.