Letter of dully authorized unit china

Dear all

I'm trying to apply for a M visa but since this week ,our embassy requires the letter of dully authorized unit..
The company that I do business with is trying to figure out how to apply for it, so if any of you guys have some kind of experience with it .can you please help?
They don't know what documents they should provide and what I should give them as well.. Please please help
Thank you