You are exactly right... "you can't tell who is who anymore."  We have a couple of clients that operate under several names/companies and we try to bill the company that send us the order.  But, way too often the company who sent us the order, and whom we billed, is not the company that pays us.  It is a nightmare trying to figure out which "company" to credit with payment.  Then, when there is a past due balance, they always tell us that "that invoice was paid with that check."  Then, we have to figure out where we credited that check so we can tell them which invoice wasn't paid.

My answer is simple... all of your invoices add up to "X"... you only paid "Y"... you still owe me "Z".  But somehow "that isn't how their accounts payable operates!"  Not my problem - if someone doesn't pay me, we stop working for ALL of their "companies."

We shouldn't have to do this.