AT&T started selling the iPhone 4 to walk-in customers, but they didn’t last long. Some stores have already exhausted their supply of iPhone 4s — and that’s bad for the Apple brand, according to one analyst.

“What is happening now certainly has done some damage to the Apple brand,” said Tina Teng, an analyst at iSuppli, in a statement to “Computerworld” ( “Consumers, questioning Apple’s supply chain management capability, have started looking for alternative devices. In particular, consumers are not satisfied with Apple’s response to the antenna issue causing poor reception and dropped calls.”

Teng was referring to mounting complaints that holding the new iPhone can impede signal strength, making it difficult or even impossible to make and maintain calls.