How to delete your Gumroad account
If you'd like to delete your Gumroad account, you first need to login.
From your Advanced Settings page, scroll to the bottom of the page, then click Delete your Gumroad account? After you've deleted your account, if you try to log back in, Gumroad will make your account "live" once again.
Therefore, if you really want to delete your account, click Delete your Gumroad account? and don't log in again. Just... just go.