British giant Vodafone's loss-making and indebted joint venture with local firm Idea was the biggest loser, being told to cough up $4 billion, Bloomberg News reported. Vodafone's Mumbai-listed shares slumped more than 16 percent when the markets opened, before recovering slightly. Vodafone Idea and Bharti Airtel, another major operator which was told to pay $3 billion, expressed their "extreme disappointment" in the decision, saying it will exacerbate the sector's financial woes.