Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
WHMCS - WHMCS is an all-in-one client management, billing & support system for online businesses.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
BILLmanager - BILLmanager is an all-in-one web hosting billing software. It provides billing automation, service provisioning, client portal & back office and support center.
Crisp Chat - Multi-channel customer support software
HostBill - HostBill is a powerful and flexible, all-in-one automation, billing, client management and support platform for online businesses.