I am using a free 30 day trial of eM Client 7, but I cannot add contact's to my list.

I am using a free 30 day trial of eM Client 7, but I cannot add contact’s to my list. Can I go back to the version 6, that worked great on my other crashed computer? I have a new computer, but some how I tried to install v-6, & I got upgrated to v-7 30 day free trial. I am not satisfied with this version.