(847) 789 in Des Plaines, IL

Got a couple of emails with attachments named "fax.pdf" from them. Opened them in sandboxed reader, found it did seem to be a blank page image, with the usual fax header identifying the phone number, but surprisingly I don't see any evidence of malware attached to it, which was what I was expecting.

Have received hundreds of blank faxes from this number. When I answer the phone, they won't tell me who's calling.