Rant if you will, but all the provider has to go on are the statistics they see at their end. With the plethora of tricks and mis-direction spammers can use to spoof the source of messages, it can be very time consuming not to mention expensive to track down the actual source. Since you are a Mac shop, it is not likely you are the actual source but it could be a Windows laptop in your shop, an infected machine belonging to one of your customers, suppliers, correspondents, etc of course without their knowledge.
