Who do i talk to about getting them banned?

~not sure where to post this sorry.

I can see he was banned: http://www.sythe.org/member.php?u=341988

 

What do i do?

 

The best way is to e-mail customer support and provide them with the username and a few chatlogs.

 

did you changed the email when you bought them?

 

@up
Changing an email won't help when original owner wants to get them back.

 

This :c I got them both like 400 elo too lol

 

Did you try to write a ticket to the league of legends support that this guy is attempting to sell leauge of legends accounts or something? Perhaps you'll get this account banned, if it would satisfy you.
You could also try to get this account back if you have any proof of riot points purchases. You'll also need to know account creation date, and few more things. Check the support faq. I wish you good luck.

You can also add my MSN, I'd try to help you with it.