How to get the VISA NOTICE ?

I have an invitation to visit an important medical program in Ruijin hospital in Shanghai, China. I have all the required documents except the VISA NOTICE.
However, when Ruijin hospital contacted the immigration office in China, they have refused to issue the Visa Notice saying they do not issue such documents for a person who is outside China. They have also said that issuing the visa is the duty of the China embassy in Colombo and the immigration office has nothing to do with it.
What should I do? What is the office/authority which issues the VISA NOTICE. (None of the telephone numbers given in the website respond.)