Smooch.io for Facebook Messenger - Message your customers from Slack, Front, a bot or anywhere!
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
Pullstring - Powering computer conversation across all platforms.
Zoho Desk - Industry's first context-aware Helpdesk Software
Conversity - Easiest way to manage Facebook Messenger chats
Salesforce Service Cloud - Service Cloud integrates customer service with social networks and provides a self-service customer portal and knowledge base system.