Can't disable email sending in PHP 5.6

Disabled mail send in a cPanel account using these instructions https://support.cpanel.net/hc/en-us/articles/1500007530882-How-to-disable-the-mail-for-PHP-to-help-prevent-email-abuse-or-outgoing-spam

but it didn't work. I believe it is because it is using alt-php (Cloudlinux PHP) is there any alternative that you can suggest me?