Very funny and strange case of rejection. I made a method called 'singleTap', that is - as the name suggests - receiving events after a single tap occurs. During the development process the function was not used and commented out, but an oversight let to the notification being left it. And then the message from Apple:

"3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs." The following non-public API is included in your application: singleTap:

Hmm. Clearly I did not use a private API, apparently I just happened to call a function the same name as a private API function... Wondering if there is a list of reserved function names, which is triggered a rejection?

Solution? I commented out the superflicial notification AND renamed the function to 'oneTap'. Just in case.

I am starting to believe the stories about the Apple store.