Greetings i'm Prince, i reside in Thailand and i wish to have a tour to China this April

Greetings I'm Frank a Cameroonian, i reside in Thailand and i wish to have a tour to PRC this April and i don't know how to do because it's really difficult issuing a tourist visa from the Chinese Embassy here in Thailand. So i wish to ask if the Cameroon Embassy can guarantee me for my trip to PRC by issuing me an invitation letter.