It would take 2 minutes to examine the phone-records and ID the call (if it occurred from that office). I used to be the monthly phone audit guy for a Pentagon agency, and I’d get a listing each month of all calls going outside of the building. You knew the phone number from inside the office, and the time-stamp on the call. So unless, they’ve reviewed this document (I seriously doubt it), they can’t say for sure that the call occurred or not.
But for this robo-sounding voice mixer, this is an odd part on the story. Why use this?
Thanks for the info. As for why they’d use the robo-sounding voice mixer, maybe they didn’t realize it was that easy to spot on the other end, since some phone voice changer products have ads purporting to sound “professional”, and since they couldn’t hear themselves on the other end.