For questions regarding the subscriptions offered by Elastic, you should use the contact form on this page: https://www.elastic.co/contact. The Sales team will then be able to discuss options with you.
In terms of when you licence for the products expire, for Shield access to the stats/info & health APIs will be blocked, and for Watcher access to the watcher API is blocked (you can't add/update/delete watches or get watcher stats),watches will keep executing and writing to the watch history, but watch actions will not be executed.
Hope that helps