I have been using BSNL prepaid 3g services for the past one year in Kolkata, the only advantage is that there is good network coverage when travelling Northeast and East India, otherwise, there is nil to none customer service, there is not transparent plan, no std rate cutter or good internet plan or charges, no option for online recharge.
Got so sick of BSNL I switched to dual sim phone and use it only for receiving calls. Don’t make mistake of using BSNL prepaid connection.