Recaptcha doesn't work

Hi, i've set captcha-recaptcha as default captcha in control panel, filled-in the keys in the plugin management, but i don't see the plugin working in the site ( www.labor-service.it/index.php/en/contact-form ).
Do i forget something ?
Another question.
Car i don't use different languages how can i manage to obtain a plain site's address (i:e: www.labor-service.it ) without the suffix '/en/' ?
Thanx in advance

Hi Marco Besana,
I'm sorry for reply late,
I check our Demo, But I can't see our template use captcha. Please check it again.
Thank you so much for empathy