Colombian lawmakers have asked Mexican billionaire Carlos Slim to appear before Congress over claims his telecommunications empire has abused its dominant position in the country. Lawmakers are seeking testimony from Slim, the world\'s richest man, to bring \"greater transparency\" to the telecoms sector in Colombia, according to a copy of the correspondence inviting him to testify. Senator Wilson Arias, of the leftist Democratic Pole, and Green Party Senator Carlos Amaya on Wednesday requested Slim\'s appearance over charges that his Claro mobile phone company overcharges customers and provides bad service. Slim is not obligated to appear before the Colombian legislature, however. Debate over Slim\'s company comes as the Colombian government considers auctioning off licenses for fast 4G wireless technology. Some lawmakers argue that Slim should not be allowed to take part in the auction as long as the market is not opened up to more telecoms concerns. Colombia\'s mobile phone, Internet and cable television market is dominated by Claro, Spain\'s Telefonica, Colombia\'s Empresas Publicas de Medellin (EPM) and Tigo, owned by Luxembourg-based Millicom International.