Approaching my client without informing me and meeting him.would it be termed unethical.?

A large transport co having a garment factory approached me to procure business for them as their machines were idle.I put in an initial order.Their MD came to my city and took an appointment with my client to meet him.This was without informing me.However,my client was good enough to call me and inform me that the MD had called for an appointment.The point is,should the MD have called me and asked me to arrange a meeting with my client or not?Just because i am the commission agent,does it give him liberty to go directly to my client,who i have introduced to the factory.Secondly,aren't there any norms to be followed and business ethics be excercised.i would appreciate an answer.as these occurences are becoming a rule in business.In short,i believe straight forward bussiness conduct is becoming a rarity.