The moment you delete any AWS resource they no longer stay associated with your account. Sometimes either due to poor internet issue or some system error your resources may remain running inspite of deleting them.
At beginning when you first start using AWS resources, Amazon sends you an introductory email with links to learn more about that specified service.
This does not mean that you are currently using the service. So dont worry this is just to -
a) provide you with links to learn more about AWS Services
b) act as reminder incase you forget the service to switch off