Everything was fine till yesterday. However, from today I have started facing a very strange problem; seems a sort of call routing problem.
When I make a call to India, the recipient cannot hear me (rather they hear their own voice back). I have tried calling different folks in India many times on five different networks: BSNL, Aircel, Vodafone, Idea and Reliance. The problem occurred with every network except BSNL (Acc to this page: International Long Distance Calls | Verizon Wireless , it should work on all these networks, which it did till yesterday). When I call the same people using my friend's phone (not Verizon), everything works fine.
P.S. I don't face this problem while making local calls, or using Google voice to call those people in India using the same phone.