MEXICO CITY -(Dow Jones)- Mexican media conglomerate Grupo Televisa (TV, TLEVISA.MX) and NII Holdings Inc. (NIHD) have agreed to terminate an accord under which Televisa planned to take a 30% stake in NII Holdings' Mexican unit, Nextel Mexico, for $1.44 billion, The decision not to go ahead with the investment comes as the 30 megahertz of wireless spectrum won by Nextel Mexico in a government auction in July faces a series of legal challenges from wireless concern Grupo Iusacell (CEL.MX) questioning the legality of the auction. In a joint press release, Televisa and NII Holdings said they have agreed to terminate the investment pact, without giving further details. Grupo iusacell has filed more than 70 lawsuits against the auction in which Nextel Mexico won a 30 megahertz nationwide block of spectrum with the minimum bid because spectrum caps set by antitrust regulators kept other existing operators from bidding on the block. Most have been defeated, although last week Iusacell obtained a court ruling keeping Nextel from using the concession. That ruling can be appealed. -By Anthony Harrup, Dow Jones Newswires, (5255) 5890 5176, anthony.harrup@dowjones.com Order free Annual Report for NII Holdings, Inc. Visit http://djnewswires.ar.wilink.com/?link=NIHD or call 1-888-301-0513