Sue Simpson writes:
We just had one of our employees use 84GB in 12 hours. She has a new iPhone 6. She received an overage message and her data was shut-off. Highest use of data in her apps indicates “Media Services.” No one knows why nor how this is possible. She was at home on wireless at the time as well.
First off, great diagnosis job on Sue and her staff’s part. If you’re trying to find a bandwidth drain, going to Settings > Cellular will show you data consumed by each app, but not in order of usage, only alphabetically. Swipe down to the bottom of that list and tap System Services, which is sorted by internal iOS processes from most to least usage.