This is a tough category because all telephone service companies have complaints on public forums. Remember that people who comment on these forums are more likely to be unhappy with the service, while happy people don't frequently take to publicly announcing their happiness with a product. Acknowledging that all the companies we looked at have some complaints, the winner for best service is Vonage, one of the first phone companies to offer VoIP for business.
Company Description: Vonage is a powerhouse in the business phone industry. The company offers a range of VoIP business phone plans that allow companies to secure their own toll-free number and use the advanced mobile features that the company offers. Their features include a reliable mobile app, desktop app, conference calling, online meetings, video conferencing, file sharing, multi-level auto-attendant, CRM integrations, call recording, group calls, and visual voicemail.

For locations where a desk phone is required but no Ethernet cable is nearby, Yealink offers an option to use it’s reliable and secure DECT wireless extender or you can use your Wi-Fi if you prefer for quick and easy desk phone placement in places where no Ethernet cable is easily accessible — an ideal solution for installations that simply cannot run new Cat6 cabling everywhere.
Company Description: Nextiva is a large virtual phone service provider and a well-known brand within the industry. They allow companies to register toll-free 1-800 numbers or local numbers anywhere in the U.S. Their setup for their service is instantaneous — once you pay, you’ll be able to begin using Nextiva right away. Their features include the ability to use their service on a mobile device and manage your calls online from anywhere in the world.