You mean the one in Pittsburgh? There's a comment from someone within the Pittsburgh EMS system with a little more information. Seems the EMS crews were all going through snow, and sometimes getting stuck for hours. Several crews tried to get to this guy but couldn't make it, and then they were told to disregard the call so they went on to the next call. None of them were told that this was a return call.

Sounds like a clusterfuck in management and operations, rather than a failing of the EMS crews themselves.