Services as well as environments can be easily deleted.
To delete an environment go to the environment index page and click "More" -> "Delete Environment" in Actions column of ready to delete environment.
Environment deletion means to kill all services with instances on which they are installed. Instances will be scheduled to delete right after you choose the "Delete Environment" action.
To delete a service go service list page and click the "Delete Service" button in Actions column. Note: If you are deleting service that was already deployed you'll need to Deploy the environment again by pressing corresponding button. In case you want to delete service prototype - it has "Service draft created" in the Last operation column (see the screenshot below) - changes applies right away.