No worries! Your work will be fully KEPT and the plugin will keep on working 100%. Here are some details:
• Your plugin will continue to work, but you will not be able to install CSS Hero on NEW (other) sites.
• You will no longer have access to CSS Hero support, updates (we had 12 in 2015 alone!), and CSS Hero affiliate program. Sad face.
• If you choose to not extend your CSS Hero plan and thus not get updates, you may eventually run into some compatibility issues as you install new updates for WordPress, your theme, and other plugins. We constantly make sure that CSS Hero is compatible with the WordPress environment, and, of course, it’s always best to keep your plugins up-to-date.