Last Friday, a lawsuit was filed in the U.S. District Court of San Jose, California, targeting none other than Apple Inc., itself. The plaintiffs were a Florida couple, William Scott Phillips and Suzanne Schmidt Phillips.

The MacBook producer looks at a $5 million class action lawsuit due to Wi-Fi Assist, a feature that caused debate since the release of iOS 9. The purpose of Wi-Fi Assist is to make sure that the phone's user has a smooth ride while browsing the Internet.

It monitors the quality of the Wi-Fi power and when it detects a slow or jaggy signal, it automatically switches the phone connection to cellular. This effectively forces the smartphone users to tap into their mobile data plan without realizing it.

By going to Settings and finding the Cellular tab, iPhone owners can manually deactivate the function. However, it is a default setting for iOS 9 and this means that some less savvy users pay no heed to it until it is too late. They usually find out about it when the Internet data bill arrives and is breathtakingly inflated.

"This is especially true, as there is no warning or disclosure when the phone switches from Wi-Fi to cellular data," the complaint reads.

Apple addressed the issue by publishing a help page that helps users understand how Wi-Fi Assist actually works, but for those who burned through their data plan already, this remedies nothing.

The couple that started the lawsuit makes the claim that Apple's behavior was both deceptive and unfair under California law, and that the tech company is guilty of negligent misrepresentation. They add that Apple falsely advertised the update to iOS 9, which led them into error.

William Anderson, the attorney who represents the Phillipses, pointed out that the couple demands compensation for themselves as well as for other Apple customers who were slammed by the big data charges. According to the federal court's rules, the sum of $5 million in damages is the minimum threshold necessary to file such a suit.

"It boils down to a decision by Apple to provide a product update without adequate warning about the result of that update," Anderson said.

Apple declined to comment on the scandal.