Disable sending email message

I have one technical question. I store messages in database from contact form (I use it for one special occasion.) I need this because I have a really lot of entries from users and my hosting provider limit sending emails (limit per day). If I leave Mail part under Form blank email is not send of course. But how does this looks like from server part? Is email send with error and server count this like “normal” email just it is not successful?

http://wordpress.org/extend/plugins/contact-form-7/