A new feature of Apple's brand new iOS 9 operating system may on the outset appear to be a very useful tool, but it could bring a nasty surprise when their bill arrives.The technology giant released their latest addition to the iPhone family earlier this month with the device going on sale last week, but its Wi-Fi assist option could end up costing users a fortune.Wi-Fi Assist works in the background and detects if there is a poor internet connection.Should it deem that there is, it...
