I started online recharge through rechargeitnow.com. It was a web only version back then. It was fast and user-friendly.
So I downloaded the app. I've never been more disappointed. It worked fine in the beginning, then it simply stopped accepting the card and began failing the transactions and recharge.
The site loading is so slow. It takes almost a year. And they never reply to the emails or the queries. There's always an automated reply from their end.
I wouldn't recommend it.