@^^ It is 200GB per month. And you do not need to recharge any more after that one time payment. What speeds are you getting? Can you kindly post a speedtest screenshot? I get around 2.2 Mbps usually, but it varies a lot.
I talked to the MTNL CC at my local telephone exchange regarding this plan. He was clear about the recharge procedures and told me that it is a one time payment that I need to make.
He also offered me the Teracom modem for 1699/- but then told em that it is not good at all and that I should buy my own modem, or use the SIM in a phone with tethering.
Next up, I looked up the various Huawei modems on sale in India, and the E122 stands out to be the clear winner.
I am going to order the modem this week and get my spare MTNL SIM recharged with Rs. 4500/-.