Business diffulculty (Hong Kong)

Hey Pros out there,
What are some of the barriers you faced when starting a new business venture?
I have been trying to knock on the doors and gain contact access to some Hong Kong owned and operated corporate business with little success. We are providing advertisement and business solution services and have been trying to notify them via email and letter pamphlet and the occasional call.
Of whom should I be getting a hold of? and how do I break through to allow more discussion to happen?
I m also all but wondering if my emails have went straight to junk.
Please Help!