Apple has become the target of numerous class-action lawsuits in the US over reception issues with the iPhone 4.
At least four suits have been filed, with the largest containing 11 plaintiffs, according to Apple Insider.
Two other cases were filed in San Francisco, and a fourth in Maryland, Bloomberg reports.
The suits accuse Apple of violating the Federal Communications Act, breach of implied warranty, intentionally and negligently misrepresenting the iPhone, and fraudulent behavior.
Some complaints also target AT&T, Apple's exclusive carrier partner for the iPhone in the US.
Because US customers can't return the iPhone 4 to Apple without having to pay a 10% restocking fee, the complainants argue that the reception issues have caused them financial harm.
As well as seeking damages, some plaintiffs are also asking courts to force Apple and AT&T to undertake an “informational campaign” to let the public know the “wrongness” of its practices, while others insist Apple should send free iPhone cases to every customer who pre-ordered the device.
The cases retail for $29 (€23) in the US.
Apple has issued advice to users about how to hold the iPhone, however its adverts show users holding the device in a different way.
The disparity has been cited in one case as evidence of misleading practices, according to court documents published by Gizmodo.