This sounds like the old copier toner social engineering scam at Google scale.

Some random employee would get a call from someone claiming to be from the copier toner supplier, asking for the name of the person in charge of buying that stuff.

The pretext might be their files got mixed up and they want to straighten it out, or maybe they're a prospective supplier who wants to beat whatever price you're paying now.

Then they make a fake invoice with that name, mail it to the company's accounts payable desk, and hope it gets paid.