title_body: How can I verify that the statistics provided by an DIY publisher are accurate? We want to publish an (e)book through an DIY publishing company. (We haven't choose one yet).
  
  How can we verify/be sure/cross-check that sell statistics of the publisher is accurate?
  
  For example, we publish our book at 'Foo.inc' and they say that they sold for us 100 books and owe us 100$ but in reality they sold 110 books and keep 10$ for them.
  
  How can we find that? What stops such these companies to do in practice such a thing? I know that's illegal but there is a real mechanism to protect the authors against this thing?
upvoted_answer: As with so many things in life you cannot be 100% sure. That is somewhat more true for digital distribution, as there is no way to check e.g. that a company bought paper for 1000 books and said it only printed and sold half of that.
  
  Unless the DIY publishing company is really small, there will be multiple people involved in faking such sales (the person doing the website, the accountant, the manager), all of them have to play along. And if one of them gets a better job the chances would be, that a an ex-employee discloses fraudulent practises. If that kind of thing comes out you can normally close your shop, and I would not want that to happen if it was mine. Building a business is much more difficult than selling 10% more, so that cheating and losing all of it doesn't make sense. 
  
  That doesn't mean that small companies are more susceptible to fraudulent activities. If you work on your own you are much more likely to lose your personal credibility.
  
  It is in my experience with companies, much more likely that payment will be late than that they try to cheat on you.