We recently ran into 2 customers who are using Go High Level, a CRM system with built-in phone service. But it is very expensive. 

Since iCare already has extensive CRM functionality, the CRM part of GHL is not needed. 

Options for calling service inside iCare:

1. Google Voice does provide an API... so, this is not an option 
2. AWS doesn't have a Google Voice-like service or a phone service similar to their SES and SNS service (used for emails and texting)
3. Found Twilio, a Programmable Telecom Provider. It doesn't have the high monthly subscription cost like GHL. The usage fee is the same for Twilio and GHL (about $0.014/Min)
   • Other services similar to Twilio are SignalWire, or Plivo.