http://www.digitaljournal.com/technology/iphone-user-says-2000-bill-shock-was-caused-by-ios-wi-fi-assist/article/449843

iPhone user says $2000 bill shock was caused by iOS Wi-Fi Assist

Posted Nov 19, 2015 by James Walker
An iPhone user who received a phone bill of over $2,000 from AT&T has said he believes the Wi-Fi Assist feature introduced in iOS 9 is the cause. It's far from the first time Wi-Fi Assist has been alleged to have caused bill shock.
The Consumerist reports that the San Francisco family's bill was over 10 times what they usually pay for a month's service. The family says it was their son's iPhone that racked up the charges but he wasn't necessarily the culprit himself. Instead, Wi-Fi Assist gets the blame.
The feature is designed to give iPhone users constant connectivity without suffering drop-outs caused by weak connections. This means iOS may choose to switch to a mobile data connection if it detects deteriorating Wi-Fi strength, saving power and potentially increasing network performance.
The issue is that using cellular data at will could push users over their monthly limits. As Wi-Fi Sense is turned on by default after upgrading to iOS 9, it's likely many people don't even know their phone is choosing to use mobile data when it experiences weak Wi-Fi in the home, incurring charges in the process. The only indication that mobile data is being used instead of Wi-Fi is the network icon in the status bar becomes greyed out.
The family say that the poor Wi-Fi range of their router means their son's bedroom has a comparatively weak signal. They say Wi-Fi Assist picked up on this and chose to use mobile data whenever he was in his room, maintaining a strong and reliable Internet connection but pushing the family over their data bill. The son wasn't aware of Wi-Fi Assist's existence and didn't realize he was burning through his data allowance when using his phone in his room.
AT&T did send a warning message to let him know he was nearing his monthly limit but this was apparently "nothing new" for the family. The text message said he was approaching 65 percent of his permitted data allowance but was not followed up by any further alerts. With iOS silently consuming data in the background, the remaining allowance steadily drained away until extra charges were incurred.
AT&T has since admitted that the text message was delivered to the wrong person. It should have gone to the primary account holder in the family rather than the son. In this instance, AT&T was willing to admit it played a part in the case and has refunded the full amount of the bill.
This is far from the first case of alleged bill shock deriving from Apple's implementation of the Wi-Fi Assist feature though. The company is currently facing a class action lawsuit seeking $5 million damages for people who have been pushed over their limits by their phones using mobile data instead of Wi-Fi.
The lawsuit argues Apple should be held to account and made to reimburse affected customers. A passage from it reads: "Apple intentionally chose to have the default setting of the Wi-Fi Assist as activated while at the same time chose to omit the likelihood of data overcharges to consumers that do not have an unlimited data plan."
The Apple website currently warns users "you might use more cellular data" because of the feature but this "should only be a small percentage higher than previous usage." The lawsuit says that the message, buried in a paragraph of text, should be made more prominent both online and in iOS itself and urges Apple to add an option to disable Wi-Fi Assist when setting up iOS.