How would responding to a phone number, one given by the initiator himself, verify that he represents a company? Couldn't a fraudster just give them his or her

How would responding to a phone number, one given by the initiator himself, verify that he represents a company? Couldn't a fraudster just give them his or her a own phone number? I would have expected that the money they siphon thanks to the likes of Apple and google would be sufficient for them to verify the numbers with a reputable third-party broker.