Hi, I used a publisher to release a mobile phone app long time ago, and have found that app legally being sold on multiple places that weren't included in the reports I have been receiving from the publisher... Now I want to use another publisher to release my iOS app in the Apple app store... How do you guys make sure that the selling reports you get from publishers are correct? Is there any way to monitor those numbers in a daily basis perhaps? Thank you.
Your access to the performance data will depend on your contract with the publisher, so it depends on what you negotiated. Hopefully you should at least be getting quarterly (hopefully monthly) data, and have the option for accountants to an audit on your behalf (at your cost if they find nothing wrong, the publishers if they do).
Legally you can get all the information you put into your contract. But there is no real good way to enforce that and it would take a lot of money if you wanted to pursue it using a lawyer. The best is that you have a good relationship with the people at the head of the company who respect and morally believe in the rights of others. If at all possible pay them a visit, nothing is better than face to face contact.
One way to verify downloads and revenue would be to use App Annie. There is a way for the publisher to give you access to your game's data without jeopardizing the privacy of their other developers or company information.