I'm sorry for my post mistake. I thought that I updated the revised information, but it was actually not updated...
*Corrent
if ( !isset($_POST['_wpcf7']) || $_POST['_wpcf7'] == ""){
// Mee News Process
foreach(....){
}
}
$_POST['_wpcf7'] != 1 means all targets except first contact form.
Thus, if plural contact forms are used, the fix code disables.
In case of !isset($_POST['_wpcf7']):
Contact form plugin is disabled or not installed.
In case of $_POST['_wpcf7'] == "":
Contact form plugin is enabled and the contact form is used in the page.
Concretely, when contact form is not used in the page, Mee News plugin runs.