Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
CallerSmart - CallerSmart is an application that is basically used for the purpose of looking up mystery phone numbers for free.
Zendesk for Startups - Everything you need for seamless customer conversations.