If you give in on this, what next will they ask? They are trying to partially take control of the business by making threats. That is never acceptable. Fire the

If you give in on this, what next will they ask? They are trying to partially take control of the business by making threats. That is never acceptable. Fire them for cause, or at least make them quit. (financially better if they quit, but they might illegally cause harm unless you escort them out immediately) Also, you don't discriminate if you are serious about running a business. You accept all legal business that is profitable.