My app has been approved, and its now on the App Store it runs correctly and in the simulator the adBanners work as they are supposed to, but the problem is that in my published app there are no ads so i first tough that it must be because of the number of downloads but as i kept looking on the internet i found that it could be because of the contract in iTunes connect, but I've filled all the contracts.
My question is : "Do I need a minimum of downloads for the ads to appear or my implementation of the iAd workbench in my app is incorrect?"
After my app was approved, it took 3 weeks to show the banner correctly. During these weeks, I sent 2 emails to Apple Developer Program to check the status. They said If you could see the test banners on your device, it's not your problem. Just be patient.
Also, the amount of ads you got somewhat depends on the number of downloads. According to most developers, the more your app is downloaded, the higher the fill rate. But even if your download is 0, you should get at least some of the ads. If you don't get any ads, it's not the main reason.
Hope this solves your problem!