That's false. Russia did not sell any S-300 systems to Iran.
google is cool.
22 January 2001
Russia is ready to sell S-300 air defense missiles to Iran. This heightens regional concerns about Tehran's desire to improve its missile technology and programs, including the Shehab-3 and -4 missile programs. According to regional intelligence sources, the S-300 systems have already been brought to Iran so that they can assess the capability of the missiles. The sale consists of missiles, launchers, and mobile radars and cost about $250 million. The system that Iran is buying is the same S-300 PMU-01 version that Russia has sold Cyprus. More than 100 Iranians will be trained on S-300s in Russia over the next six months. More than 300 Iranian military officers and technicians will receive training in Russia in several other fields. According to intelligence sources, half of them will receive long-range missile technology training, while about another 30 will take courses on nuclear programs. Iran has asked Russia to sell them the Kamov Ka-50 attack helicopters, submarines, and launchers for the Shehab-3 missiles.
—Metehan Demir, "Russia is Poised to Sell S-300 Air Defense Missiles," Aviation Week & Space Technology, 22 January 2001, p. 19.