New York :  Apple Inc. was sued over reception problems with its new iPhone 4 by consumers who accused the company of unfair business practices and false and misleading advertising.

A New Jersey resident and a Massachusetts resident who had bought the new mobile phone filed separate complaints on Wednesday at a federal court in San Francisco, each seeking to represent other iPhone buyers in a class-action, or group, lawsuit. A separate complaint was filed yesterday morning in Maryland, alleging Apple and wireless carrier AT&T Inc. were negligent in marketing the phone.

Criticism

The June 24 introduction of the iPhone 4 was marred by criticism that signal strength diminishes when users cover the bottom left corner of the phone with their palm. The iPhone, which debuted in 2007, has become Apple's top-selling product even after users reported glitches and dropped calls with previous versions of the device.

"Apple's sale of the iPhone with this unannounced defect, assuming Apple's prior knowledge of the defect, constitutes misrepresentation and fraud," Christopher Dydyk of Cambridge, Massachusetts, said in his complaint. "In omitting to disclose the defect in the iPhone 4, Apple perpetrated a massive fraud upon hundreds of thousands of unsuspecting customers."

Apple, which sold more than 1.7 million of the new phones in its first three days, has recommended users hold the phone differently or use a case to solve the problem. Apple is selling its own iPhone 4 cases in six colours for $29 (Dh106) each. They're made of a piece of rubber known as a "bumper," which surrounds the outer rim of the phone. Dydyk, in his complaint, asked that Apple ship a bumper for free to customers who pre-ordered the device.