I'm on T-Mo but have a Samsung Galaxy S3. I noticed this week that my mobile data usage was massive. Just this week I've used nearly 2.5GB. My normal usage is less than a GB for the whole billing period. I'm wondering if the iOS 10 issue is hammering the T-Mo network and causing my problems. My data usage shows that it's my email app that is using all the data; I have an Apple email acct, maybe the combo of the two things is affecting me?