TWOV for Iranian citizen in Shanghai Pudong International Airport

Calling the embassies will always bring you so many unnecessary headaches, trust me. Instead of telling you the real thing, they have just sent you to another address. This is all useless because the embassies in general don't have any jurisdiction over transits because this is the filed of Chinese immigration. Anyway, not to complicate, you are definitely eligible for 24 hour visa free transit and you don't need any kind of visa.

By the way, if you want, you can google "People's Republic of China border entry and exit inspection agency" and you will find several websites and links that you can use them. Also, you can call: 0086-21-96990, a number of relevant authorities at Shanghai Pudong airport.

You should print out your flight tickets and have the printouts with you. Also, keep in mind that you need a valid Schengen visa in your passport to be allowed to start your journey.