Prevent “double click on submit button” related problems?

Hi,
several “digital illiterate” users double click on form submit button.

The actual result with Contact Form 7 is that: the form is instantly submitted twice, the email sent twice, and worst of all the form fields are reset and the info message disappears too quickly to be seen by the user.

May you kindly solve this?
Please don’t underestimate this problem, is quite spread.
Thank you.