z visa conversion help required

Dear sir

I have come to China on Z visa but the problem is my company couldn't prepare the documents in 30 days as there were 7 nationla holidays .So just after 2 days of my z visa expired i went to the police station with all the documents and they didn't accept it.They are saying that it is already expired.
Noe please let me know if there is any other way to help me .Thanks