Two: The answer to each and every one of the questions you are asking me is contained in the email to which you are replying. They're not even hidden. They're the whole point.
Three: The same email gives you the name and phone number/extension of the collector you should be contacting.
Four: If this is representative of the way you run your business, it's not hard to understand why your vendor has referred you for collections.
Five: I have not had enough caffeine this morning to take your idiocy in stride. I shall therefore mock you on LJ.
And people wonder why I'm abjectly grateful my position generally doesn't entail dealing directly with these people...