I have no idea why you have comments when you have then turned off (they are probably hitting a url and calling the addcomment method directly but as for editing and deleting comments you can moderate them in the 'Comments' tab in the cms (top bar). If you keep getting spammed then you may want to add MathSpamProtection to it as this will prevent people hitting the url constantly.

You can turn MathSpam on by adding this to your _config.php

MathSpamProtection::setEnabled();