How to remove your Roblox account
Sadly, you can’t delete your Roblox account. Obfuscate it using the info below, then complain about it by sending a mail to info@roblox.com.
More info: https://www.roblox.com/Forum/ShowPost.aspx?PostID=49252396
Helpful Trick: Obfuscate your profile info.
Because most accounts and profiles at Roblox cannot be removed, we suggest you login and change your account and profile information altogether.
Make sure you are logged in to your account on the site and click on the profile or options settings. Locate the fields with your personal info (email, name, address) and fill in generic, random information instead. If you can only select from several fields, change anything personally identifying. If possible, use a homepage/URL field or long text field (such as Description) and put this line in it: https://remove.org/removal-requested. This may encourage webmasters and admins to create an easier removal outlet.
Helpful Trick: Removing online data
Publicly visible text/images often aren’t properly removed even when you succeed in removing an account. Try editing or removing them manually before removing the account itself. If you’re unsure what happens to your tracks: this can be found mostly in the Terms of Service/Privacy Policy; otherwise you can always contact Roblox and ask personally. By the way, removal requests don’t necessarily mean your data will actually be removed (e.g. due to legal obligations).
Helpful Trick: Remove third-party logins
If you signed up for Roblox using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Roblox. Click here to find out how.
my account was hacked and I want it REMOVED