Avaz Mano

Here’s how I did it:

function action_wpcf7_mail_sent($contact_form)
{
    $submission = WPCF7_Submission::get_instance();
    if ($submission) {
        $posted_data = $submission->get_posted_data();

        $num = $posted_data['_wpcf7_groups_count']['my_field_group_name'];
        for ($i = 1; $i <= $num; $i++){
            echo $posted_data['my_repeater_field_name__'.$i];
        }
    }
}
add_action( 'wpcf7_mail_sent', 'action_wpcf7_mail_sent', 10, 1 );