Apologies for reviving an old topic, but I'm experiencing similar problems. I have an iPhone 6s with iOS 13.3.1. I don't use iTunes at all but it keeps eating away my cellular data. Also 'push notifications' use data even though I've disabled the notifications. As far as I'm aware, I've switched off everything to do with iTunes, so hopefully someone here can help me out a bit. How are the ones who also raised this issue currently dealing with this?