NAGPUR, JUNE 15: The central excise and customs department recently issued notices to 439 cell phone owners in the city who had allegedly purchased handsets from the grey market in a clandestine manner to avoid the hefty customs duty.The customs department has demanded duty ranging from Rs 6,868 to Rs 18,986. The duty works out to be more than the actual price of the cell phones. Many cell phone users had purchased `Slim cards' from cellular service provider, BPL US West, but procured handsets from the grey market.The company offered subsidised handsets, but could not match the `dirt cheap' prices of the grey market. Since smugglers, who procure the illegal sets, are out of the authorities' reach, the customs department is collecting whatever revenue it can by chasing subscribers. It has written letters to subscribers possessing illegal mobiles and has asked them to abide by the rules.