Twitter has put some effort into the "customer service" use case. https://www.forbes.com/sites/shephyken/2016/04/30/how-to-use...

At a basic level, you could think of it as providing the content for the audience - the inventory that is sold to advertisers. Twitter as we know it would not exist if all the users were tweet consumers, and none were tweet producers.

T-Mobile is great example of a business providing customer service over Twitter.