roquelage on "[Plugin: Contact Form 7] Contact form 7 sending various emails"

Hi

I´m receiving an email for every click the user makes on send button.

Sometimes is 1, other is 9. How can i limit the email sending to 1 at a time( or every 30 seconds) or make faster the sending?

Other solution will be welcomed with arms opned!!

Thanks!

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