There are official channels to know whether the other party is qualified to be an intellectual property agent, agency, accounting firm, lawyer, etc. Generally there are trademarks, copyrights and patents. Those who are qualified for trademark copyright may not necessarily be qualified for patent.
First of all, regarding trademarks, you can go to the Trademark Office in official website.
Then, if you are a patent agent, you can go to official website, China Agents Association.
Feel free to ask me if you have any questions ~