Disabling the PHP function mail() has a good reason behind it — security and IP reputaion. The mail() function sneds mail without following any mail standards, thus the shared IP gets blacklisted at point. Also there is no certain way to limit how many mails can be sent from the server per mail which also screems like spam.
Unfortunately if cannot be enabled, if you need to send mail then please SMTP via creating email in your cPanel account.