How does one deal with a UNICOM operator directing aircraft like at a towered airport?
You're almost certainly talking about a UNICOM operator, who is just an airport (FBO) employee who gives information to pilots on their request. The FAA's Pilot Handbook says:


  UNICOM is a nongovernment air/ground radio communication station which
  may provide airport information at public use airports where there is
  no tower or FSS. On pilot request, UNICOM stations may provide pilots
  with weather information, wind direction, the recommended runway, or
  other necessary information. If the UNICOM frequency is designated as
  the CTAF, it will be identified in appropriate aeronautical
  publications.


The important point is that UNICOM is not ATC. A UNICOM operator cannot give you instructions, clearances or require you to do anything. He can only give you information, and as PIC it's up to you to decide how to use that information.

The article that Porcupine911 mentioned is a great example of that. A student pilot thought that UNICOM was telling him which runway to land on, whereas in fact the operator was only recommending a runway (presumably based on the prevailing wind or whatever). Unfortunately, the operator recommended the opposite runway to the one that was actually in use by other pilots.

Like pilots, UNICOM operators vary in their experience and competence. A good UNICOM operator (in my opinion) will give you the local wind and altimeter information, tell you if there are other aircraft in the pattern or nearby, tell you which runway is in use by those aircraft, and give you any essential safety information (like a closed runway). But as PIC, I'm still going to listen to CTAF and AWOS and look for other traffic before choosing a runway and joining the pattern. It's also common for no one to reply to a UNICOM call (because the operator is out fueling aircraft in his other role as lineman, for example), in which case you're going to have to sort things out without it anyway.

So there's no need to "report" anything: UNICOM operators are a well-known and official service, but you have to know how to use them and what their limitations are.