Basically you just drill in their help until you get to a specific topic (try something not related to abuse/TOS, since those specifically tend not to have that link for some reason).

Then, on the bottom of the right side-bar, you get an option to contact them, which takes you to a login screen. You can skip it, and get to a page where you state the exact nature of the problem. Currently it is located here:
http://www.blogger.com/problem.g?skiplogin=yes
But they moved it in the past, so if it changes again just try the long way.

Then just pick whether you want to report a spam blog, or “another TOS violation”, and you will be taken to a form where you can detail the issue.

From past experience you will almost immediately receive an automated message telling you that a real person will get back to you as soon as possible. And about three days later a real person actually will.

That first real person tends to be a little… dense, shall we say? So either originally state the issue very very simply and clearly, or expect that you will be required to reply to that person with a different way of saying the same thing, and a request to pass it upward.

Eventually it does get to someone who pays attention.
They then close those blogs.

Sometimes they even catch it if these blogs are opened again, by the same user, a few hours later. Sometimes they don’t.

Good luck.

At the bottom of the page there is a link that appears to deal with all questions, but may only deal with privacy issues. Either way, I suspect that if you write to the Google / Blogger people at that email address, they will point you in the right direction.