Last week, it was reported that a growing number of iPhone 6 and iPhone 6 Plus users were finding their smartphones had fallen victim to the so-called "Touch Disease." Apple still hasn't officially acknowledged the hardware issue, leading to some owners filing a proposed class action lawsuit against the company.

The problem is a result of the phones' bendability, which causes the touch controller chip's soldering to crack eventually and start to lose contact with the board; a problem that's made worse through dropping and rough handling. As this happens, a flickering gray bar appears at the top of the iPhone and the screen starts becoming unresponsive, up to the point where it no longer registers touch.

This same flexibility brought about the "bendgate" phenomenon. The issues led to Apple stiffening the next generation iPhone 6s and 6s Plus.

Three plaintiffs filed a lawsuit against Apple over the weekend, alleging that the company knows about the design flaw but refuses to acknowledge or repair it, thereby violating several California consumer protection laws.

All three plaintiffs purchased iPhones that eventually showed signs of Touch Disease. Apple refused to repair the devices; instead, it offered to replace them at a cost of more than $300.

"Apple has long been aware of the defective iPhones," the complaint says. "Yet, notwithstanding its longstanding knowledge of this design defect, Apple routinely has refused to repair the iPhones without charge when the defect manifests."

The plaintiffs hope to elevate the case to "nationwide class" status to include anyone who bought an iPhone that suffered from Touch Disease.

Todd Cleary of California, Jun Bai of Delaware and Thomas Davidson of Pennsylvania have also accused Apple of fraud, negligent misrepresentation, unjust enrichment and breach of implied warranty. The plaintiffs are seeking unspecified damages.