Who called from 5715580000

Who is this?

Got a fax from this number. Trying to call it back to confirm that it's a fax, but it's constantly busy.

Correction: Received a call from a fax machine.

Person keeps calling creeping out all of the employees!

A guy called my wife from this number and said he was the Inspector General and had recieved a call from her phone earlier this morning.  The caller told my wife the gentleman on calling from her phone number had an accent and didn't leave a name.  There is no record of a call being made on my wifes' phone.