How to Contact Form 7 Prevent Duplicate Submissions
Install the cfdb7 unique field plugin. Then we need to add a shortcode "unique" after the submit button shortcode.
It will prevent multiple submissions.
Example: [unique email, your-phone]
How to Change the Error Message Unique Field (CF7)?
We can change the contact form 7 email already exists error message from the wp-admin.
Go to wp-admin > contact form 7 > select form > messages > search "Field value that the sender entered is already submitted". You can edit and save the contact form.
More details about the plugin Download CFDB7 Unique Field Plugin Feel free to PM
It does not need any programming knowledge. You can add a simple shortcode "unique" without any complex coding skill.
The "Contact Form 7 MySQL database addon" includes this plugin also.
FAQ:-
1. Can I install multiple websites?
Ans - Sure, you can install multiple websites.
2. Where can I install the Contact Form 7 unique plugin?
Ans - You can download from https://ciphercoin.com/downloads/cfdb7-unique-field/