Hey @User764 Racheal from the support engineer team here
I'm afraid it is not possible to forward those emails out automatically, it also isn’t possible to disable your @intercom-mail.com address. With that being said you can still view all of these messages in the conversations tab in the inbox, and be notified of them themselves by email, but there's no hard and fast way to stop customers from mailing that address other than telling them directly to email another address for support.
You can also turn off email forwarding - you'll just need to disable it in your email client. But that won't stop customers who already have their @intercom-mail.com address from sending emails to that address.