Vodafone Group Plc said on Wednesday it had begun an international investment arbitration against the Indian government in a more than $2 billion tax dispute, after the two sides failed to find a solution through talks. Vodafone said it filed the arbitration on April 17. The long-running tax dispute is over Vodafones acquisition of Indian mobile assets in 2007. In 2012, Indias Supreme Court ruled in favor of Vodafone saying the company was not liable to pay any tax on the deal.