The period of patent application has been very long!
I don't know how you negotiated with each other.
Patent applications can be divided into three stages: acceptance, examination, authorization or rejection.
Generally, the acceptance speed is very fast. When accepting, you will receive a "patent acceptance notice" issued by China National Intellectual Property Administration.
Patent application is a legal matter, and few people promise to authorize it, just like a lawsuit. Few lawyers say they will win the case for the same reason.
Generally, in this line of work, you pay the money first, and then you start writing legal documents. If people have written all the patent application documents for you, you should pay! At least, pay when you get the admission notice!