Jetpack is a WordPress plugin that supercharges your self-hosted WordPress site with the awesome cloud power of WordPress.com.
In order to use Jetpack, you need a free WordPress.com account. If you're having issues with a specific Jetpack module, you can check the support documentation for that module here. You can also browse the Jetpack support forums on WordPress.org.
Jetpack also offers private support. You can contact the support team via this contact form.