don't keep us in suspense man...

if you fire them, they go out of business, or get bought out, the issue is the same. Try and deal with each client as they come up. Let them know that their business is important to you and you will do your best to maintain what they have.
Also let them know that if you were to continue with the current control system, you would be out of business, thus not be able to take care of them. Most clients see the light. This is one of the toughest jobs we face in our industry. Most factories could care less about your clients...we do. Most, not all, as there are exceptions, care only about their bottom line. They really forget that it is the customer who keeps us all in business.

Bottom line...take care of the client!

my nickel,
RR