not working with contact form 7

i installed WC chapta, set it up and copied [wpcaptcha wc]

the I pasted [wpcaptcha wc] in my contact form adding after submit button the same code above, that is [wpcaptcha wc], and saved

But when i check on the web page no captcha appear

The i got back to contact form config. page and added <p>[wpcaptcha wpcaptcha-728]</p> before submit, but yet on the web page nothing appears

here is web page link https://www.changemaker.it/contatti/

The page I need help with: [log in to see the link]