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

ProsperStack - Subscriber retention done right.

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

Raaft - Reduce SaaS churn

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

ChurnKey - The only platform that fixes every type of churn for you.