How do I cange my User ID or delete it?

I accidently choose wrong user ID: “iejson” (for docker & docker cloud)
I want to correct it to “isjeon”.
I sent a couple of email to customer service to change the ID, but they never reply me back.
my email is "isjeon@vision.snu.ac.kr"
Do you guys know how to change my user ID?
or at least how to delete my account?