South African Visa's

Good Day,

I am from South Africa and am travelling to Honk Kong (on holiday) on the 6 April (for 3 days).
I would like to spend a day in Shenzhen (very last minute decision) to visit some of the baby wear factories (I am interested in introducing a new brand in SA).
I went to the consulate today and they told me that I need an "Invitiation" from the factory:( I am now frantically trying to contact the factory to ask them if they can please send me an invitation (bearing in mind they dont know who I am).

Is it possible for me to apply for a different type instead of a business one? As I am not going there on official business and I am really only going in my personal capacity to have a look at the possibilities. And after all I am only going to spend 1 day in Shenzhen.

What are my options?

Many thanks
Tammy