Received call from this number. No message left

Received a call from this number. No message left.

Recieved a call again from this number, just like the first time, no message was left.

Got a call from this number and yes no message left. Caller ID says APAX??

Called us at Darling International asking for ( ex employee ) told him that person did not work here,

went off on me said he did work here and wanted to speak to my supervisor and what was my name.

Very rude did not seem to understand that person is not on our payroll.  Called and talked to his supervisor, did not hear back from them,  no big surprise here.