Where do we report developers violating the rules?

I found an application violating the Apple Guidelines (specifically it is recording my screen/audio without permission/telling me when it is supposed to be only a simple audio call and proceeding to sell such data per their T&S) and would like to report said Dev. If I have to follow the rules and my clients do, I would prefer this app developer do too. Especially since their are kids as young as 13 on their app (and younger)