Thank you for using our online answers forums! If you deleted your Slingbox ID from the directory, there is a way to get it back. What you will need to do is a hard reset on your Slingbox. You can do so by holding your reset button down for 33-35 seconds. Once you have a solid network and a solid power light, you will then go to setup.slingbox.com (unless you've a Slingbox 350 or Slingbox 500, then you need to go to newwatch.slingbox.com) and reconfigure your Slingbox. Once setup is complete you will see your Slingbox ID reflect upon your account and the Slingbox will appear back in you directory. Please see link below.
I hope this help! Please do not hesitate to reply back if any further assistance is needed.
Sling Moderation Team.