Ali talks about slack managing customer issues in a growing organization. They use Zendesk :)
The first thing that I'd like to point out is that support is probably not your end goal.
If you guys are sitting here, my understanding of this community is that you are probably developers. Perhaps product managers, maybe sales, but most of us don't go to college going, "I'm going to learn how to support a product. I'm going to make a product just so that I can have people who I can support with it. I just want to answer emails all day. It's going to be so amazing."
While we are making things because we want people to use them, we want to solve their problems, the fact that we need to support people as we use those things generally isn't the thing that we have in mind when we start a new project.
I'm sure that none of you left your confusing elects or your weird features, your gross bugs in the product just so that people would have to talk to you. But it's there, and we all have them, and people need to talk to us.
While it's not part of the business that you want to deal with necessarily, it's a necessity of your business. It's like hiring your accountant. It's like hiring your cleaning service so that you don't come in to your own overflowing trashcans every day. It's just part of getting work done.