Every cell phone should have a unique factory-set electronic serial number (ESN) and a mobile identification number (MIN). A cloned cell phone is one that has been reprogrammed to transmit the ESN and MIN belonging to another cell phone. Scammers can steal ESN/MIN combinations by illegally monitoring the radio wave transmissions from the cell phones of legitimate subscribers. After cloning, both the legitimate and the fraudulent cell phones have the same ESN/MIN combination and cellular providers cannot distinguish the cloned cell phone from the legitimate one. Scammers can then run up expensive toll charges and the legitimate phone user gets billed for the cloned phone's calls. Alert your service provider if you see unauthorized calls or charges on your account.