Identifying and processing of unreturned calls in IPBX

An apparatus, comprising:

• a first processing circuit communicatively coupled to an internet-protocol private branch exchange (IPBX) server configured and arranged to route Voice over Internet Protocol (VoIP) calls for a plurality of end-users having respective VoIP-enabled devices communicatively coupled to the IPBX server via a circuit-based communications network, the first processing circuit configured and arranged to
• receive call event messages from the IPBX server for calls routed by the IPBX server;
• and
• generate, from the call event messages, call summary metrics for call participants of the calls routed by the IPBX server;
• and
• a second processing circuit communicatively coupled to the first processing circuit and configured and arranged to:
• retrieve, from a secondary data source, data specifying non-voice communications with at least some of the call participants;
• identify, from the call summary metrics and the data specifying non-voice communications, a set of incoming calls to the IPBX server that were unreturned by either voice or non-voice communications;
• cross-correlate the identified set of incoming calls with a set of callers identified as having higher priority for returning unreturned calls;
• assign, based upon the cross-correlation, the respective and different priorities for the incoming calls;
• and
• store data indicating the assigned priorities.