Shanghai's Xuhui District Court will mediate between a Jiangxi province man and a Best Buy store on March 20 in a dispute over an Apple iMac computer.

Zou Hongqing said he arrived in Shanghai last week to sue Best Buy, an authorized distributor of Apple.

The 45-year-old photographer bought a 27-inch iMac in September 2010. After one year of use, Zou said he discovered that the screen was blurred by dust.

"The dust somehow got inside the screen. You simply cannot get to it by removing the glass," he said.

Zou said he contacted Best Buy and Apple, asking for a replacement or repairs. Apple's response was that the warranty he purchased did not cover dust and that his is a stand-alone case.

On Wednesday, Zou threatened to smash his iMac computer outside Best Buy on Shanghai's Middle Huaihai Road. He was soon asked to come into the store but accompanied by 10 police officers.

"I told them I need a refund, and they (Apple) owe Chinese users an apology," Zou said.

Apple has declined to comment on the incident.

Apple had said earlier that smog, rather than a design flaw, caused the dust problem, provoking outrage among Apple users nationwide.