Contact Form 7 problem

I am having problems with Contact plugins. I tried several before contacting the theme developers. They suggested Contact form 7, so I installed it. It is doing the same thing that all of the others were doing, which is failing to send email notifications that someone filled out a form on my site. The latest version of Contact Form 7, which is what I have, is supposed to validate your form. I’m wondering if the validate part is something that works in the background and only pops up if something is wrong. The form also doesn’t give the drop down message that the form was submitted. I’ve tried to follow the directions, but all variations have the same results.