This post is old enough that you should probably start a new thread… but since I was in my email right now here is the answer.
Make sure you have disabled comments as described above AND (this is part that always got me) if you have posts or pages that were created BEFORE you changed that setting you will need to disable comment on the page itself.
Go to posts and select “quick edit” for the post that still has comments showing. in the menu that opens look for a check bock that says “allow Comments” Make sure that box is unchecked. You will need to do this for every post or page that is currently created if you want to disable comments across all posts and pages. I suggest looking at bulk changes if you have a lot.