I apply for business visa but before that i need an invitation letter by Chinese embassy in china

i got the recommendation letter from Chinese embassy in Pakistan as they attested my companies NTN document and told us to give it in Chinese embassy in china to get the invitation letter,
this was the procedure told me as i haven't visited china in past 5 years for business trips.
now our concerned person is saying its difficult to get it under the summit in sep G20.
please guide as i have important business meeting in January.