If you are subscribed, you can cancel the subscription from Admin > Cancel Subscription and account will be suspended after the grace period (which begins after the date till which your account is already paid)
Accounts that are not paid expire after the trial period and grace period is over.
When an account is suspened, all the product data is removed. If you want to remove the profile data you can do that from Admin > Edit Profile.
A suspended account can be re-used by simply logging in again and starting the subscription from Admin > Start subscription.