Well, promoting their clients would be a part of the service that they preform and in their own self-interest. The claim of privacy doesn't make sense. It's the company which is authoring the privacy policy.
On the other hand, if they are shady, what is the motive? If a shady Chinese company wants intellectual property, it just steals it. They can publish your work with or without your agreement.
In all likelihood, this us a scam similar to the old Nigerian Princess racket. They build trust and excitement until they hit you up for money. Your instincts to suspect a scam look correct. Take it as a compliment t that y you were targeted. Unless their is some huge and unlikely misunderstanding due to a translation error, you may be best off ignoring them
...or you could go the other way and scambait them. If you have the time and inclination, you could these guys (or guy) and purposefully eat up their time.