Did you try Informatica SMS? They had a lot of options Twilio did not. They also have a list of countries and rates.
I'm not sure who would do this specifically for India, but the key would be to interface with the SMS provider with API or webhooks if a local provider can do this.
Hoosh Marketing provides a 2-Way SMS solution that can be configured to support any SMS gateway and multiple gateways simultaneously, so you have full international coverage.
You can try an interactive demo in the website and see how the platform works. I hope it helps!