i use t-mobile & get free data pretty much anywhere in the world....i also get free wifi outgoing calling & incoming calls are cheap when on international roaming....not sure if you can grab a t-mobile sim for just the time you are here but that might be worth exploring....
the alternative is to get a local sim here....they are pretty easy to get at the airport....data & calling is extremely cheap when compared to rates in the us....pick up either a jio or airtel sim....
jio is running a scheme where you have free incoming & outgoing calls, free sms & 1gb data per day till the 31st of march....i believe the sim itself will cost around inr 200 to buy & activate....after that its all free....there have been some reports that foreigners have not been able to get a jio sim because an aadhar card is required to activate the connection which only people living in india can have....you could always ask a friend or your client to get one for you to use while you are here....
the alternative would be airtel....you can get that at the airport & all you need is your passport & picture....the rates are pretty low & you will probably end up paying less than inr 1k for the full month for all your calls, data & sms....