Cheddargetter VS Totango

Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

Pabbly Subscriptions - Pabbly Subscription is a recurring billing & subscription management software.

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

HelpScout - Help Scout is a simple, straightforward way to provide excellent support