You have two separate email address settings at WordPress.com. Have you entered two different email addresses at these locations (see below) or have you entered the same one at both locations?
Blog notifications for the admin (like comment moderation, Likes, new subscriptions, etc) are sent to the email address at Settings -> General in the Dashboard.
Personal notifications (like comments on your post, subscription emails, and upgrade renewals) are sent to the email address at Users -> Personal Settings in the Dashboard.
See also > Issues Changing your E-mail Address > http://en.support.wordpress.com/email-address/#issues-changing-your-e-mail-address
Provided you are logged in under the username account that registered the blog you can delete the blog by using these instructions. http://en.support.wordpress.com/delete-site/
Please note that deleted blog URLs are not recycled.
You can make the blog private and use it as a test blog and backup blog. http://en.support.wordpress.com/settings/privacy-settings/
You can hide it from dashboard display as well. http://en.support.wordpress.com/my-blogs/#my-blogs-dashboard-visibility