To delete your account, first go to your profile and press "Edit profile". From here you can go to "Delete account". After that, a window will appear where you have to confirm that you want to delete your account. However, if you have a current subscription, this will only happen after the subscription expires.
To unsubscribe from your account, first go to your profile. Now press "Unsubscribe" (the button is located at the very bottom).