Fraudulently forwarded email recovery

Hi all,

Over the last few days, my in-laws were not receiving messages and ultimately I figured out that their email was hacked into, the password changed, and they had started forwarding all the messages to a fake address that they had created in hotmail.  Is there ANY way for Xfinity to recover the forwarded messages so at least they know what/who was affected?  The messages are not in trash nor does it work to "receover deleted messages" as they were not deleted in the typical way, they just weren't saved after forwarding to this fraudulent address.

I'd be grateful for some guidance.