Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Kayako - Help Desk Software and Customer Service Software by Kayako. Improve customer satisfaction, increase sales.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
MeisterTask for Freshdesk - Meister your customer support tasks
Better Uptime - We call you when your website goes down