Why does this site ask for my user id when loging in when I have to enter my email to log in? 

I just created a whole new account because my user name was not recognized, then after doing so, I decided to enter my email to see if I could log in that way and that worked.

It should say "email address" and then "password" if that is what it needs to log in. Asking for the user name, but really needing the email address makes no sense.

So now, how do I delete my new account I just created with the user name "Singletrackmack" with a k at the end?