Collection Consultants Threatening, harassing, stalking, lying about the law Glendale, California

I have been harassed at work by these people on a continual basis via phone messages.  The calls are threatening and include the agency lying about attempts to serve me with legal papers for a law suit.  My work would tell me if someone wanted to see me, which no one has.  The doorman at my office told me no one has been asking for me.  No one has shown up at my door looking for me.  No one has shown at my PMB address looking for me. 

Second of all, I have never had laboratory work performed at this facility which I am being billed for.  I only go to Hoag Hospital, and my physician's office (they do not use this laboratory).  This is fraud.