Virtual Call Center Creation & Setup

The individual chosen for this project should be experienced in establishing and configuring virtual call centers. I am uncertain as to which software platform would be best for my needs, so I am open to suggestions, with options such as Skype, RingCentral or Cisco Webex being potential choices. The main aim is to support both outbound and inbound calls, with the added functionality of transferring calls between different agents. Furthermore, I am in need of a toll-free number. Your experience in this field is paramount, especially with handling both customer support and sales calls. Please include your relevant experience in applications.