cPanel & WHM and DirectAdmin, as root:
cd /root/iam4hosts && bash install --uninstall
This removes the plugin files, cron job, panel registration, and the plugin's database and its user.
Plesk: Extensions → My Extensions → Inactive Account Manager → Remove. The scheduled task is removed first, then Plesk deletes the extension's files and database.
Uninstalling never changes any hosting account. Accounts the plugin already suspended stay suspended until you unsuspend them in the panel. If you have a Premium licence you no longer need, cancel it in the client area too (see How do I cancel a licence?).