Registration Form Database Path

I’m using ultimate member which allows me to have users accounts, in their account i have created contact form 7 that they should fill but i want the user to be able to only fill the form once just once, so using PHP i created a PHP that checks if the contact form 7 database has this e mail it refuses to submit the form (using the path wp-content/plugins/contact-form-7-to-database-extension/CFDBFormIterator.php)which is fine, but if the user entered a different e mail the form will go through which is the issue, so i want the user to be forced to enter the same e mail he registered with and not any other e mail, i was thinking of creating another PHP that checks if the e mail is not in UM registration form database but i cant find the registration form database path.