It can depend on the company, but some companies literally don't have a public facing email anymore. I was trying to get in contact with Bank of America of whom

It can depend on the company, but some companies literally don't have a public facing email anymore. I was trying to get in contact with Bank of America of whom I am not a customer because they were (and still are) spamming my inbox and the only human contact I managed at all was via their support Twitter page. Not that it got me anywhere in the long run.