Iris,
  I have checked with a few attorney's that are friends of ours, and they stated that as long as what is being written is true, then slander nor defamation of character can be won; the company in question would have to show that 90% of what is being said was false. Maybe if an on-going list is made, then we could put what date their name was added and whom is adding it, so if there was a legal issue, the company would know who to pursue and that person would have the legal documentation to back up what they are saying. We keep notes of whom we've contacted and how many times for our personal documentation. And Jay, have you ever considered the fact that maybe they are paying on time now, because they were on the list at one time? If it is an on-going list and someone knows a certain company is now paying, then a side note could be made. And just because their name is on the list, doesn't mean someone will not do work for them, it just gives them a heads-up and they can remain cautious. I believe this is the most effective tool for protecting ourselves and it seems to be working. I'm sorry if people think it is unethical. I think it is wrong for the companies thinking they can stick a small company with a large bill, because nobody will communicate, thinking it is unethical.