I don't think Indian SaaS startups should worry about the $500/transaction limit imposed by RBI. That's pretty huge for SaaS prices.
If you indeed want, there are plenty of alternatives:
http://www.braintreepaymentsolutions.com/ , http://chargify.com/ , http://spreedly.com/ , https://cheddargetter.com/ , http://recurly.com/
Of these, Braintree looks most popular and is used by many big names.
