As you well know a  virtual phone number in India is the easiest way to boost efficiency to your business.You can track & route calls to your agents without burning a hole in your pocket.

There are quite a number of Virtual number providers in India.

But why don't you try Exotel. Big Companies like UBER, OLA, Peppertap use their services like virtual number, Number masking etc in INDIA.
They are quite cheap too. Here's the link :

https://exotel.com/virtual-phone-number-india/