Certainly, they will have to prove somehow that their app was ultimately removed owning to a competitor's pressure. If they can do that, then the monopolies act and everything will come into the picture. I'm not insinuating that any competitor is doing this to Uber, but that's pretty natural and apparent in this case. Naturally, the store is Apple's business and app publishing is a means of income. No sane business will refuse a business prospect on the grounds of "I don't like you". The only reasoning here is that a competitor is involved. But yeah, proving that in a court of law is a different thing altogether which Uber has to manage.