Hello tmiskiew,
Did you managed to pass the review with your app? I have a similar issue (with another third-party service) and trying to get through this review rejection reason.
AaronShwartz
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution