What are some alternatives?
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Dialpad - Switch is a cloud-based phone system built for Google Apps users.
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
CrazyCall - CrazyCall is cloud based platform for sales and marketing teams doing cold calling, market research, information or loyalty campaigns.
Viber - Free and secure calls and messages to anyone, anywhere. Keep your conversations going no matter where you are.