There are plenty of companies that sell their own products and services alongside being a retailer for third party products. Even in that situation, I don't be

There are plenty of companies that sell their own products and services alongside being a retailer for third party products. Even in that situation, I don't believe there is any legal or moral requirement that they stock competing products (unless in a monopoly scenario). It might seem like a crappy thing to do but the alternative is completely unsustainable.