iOS data usage specifics - iTunes Accounts I'm trying to find out what does "iTunes Accounts" traffic stands for on iOS, since it has gobbled 850MB on cellular data in 13 days.
I have iTunes Match on but have disabled the Music app to access data on cellular networks.
I'm on iOS 8.3 since today, data was consumed on 8.2.
Probably iTunes &amp; App Store background downloads.

You can prevent these, so it only updates when you're connected to wifi, in
Settings > iTunes &amp; App Store…  by disabling Cellular Data
[I also prevent all automatic downloads, so mine only updates from iTunes itself, on my Mac]