I am in the same situation, application rejected for china PCC for not covering entire period. I have stayed from 2009 to 2018 multiple times, all are in business visa except from 2016-2018 those period I was in work visa. I manage to get PCC for work visa period i.e from 2016-2018 along with that I attached explanation letter saying PCC can't be obtainable for business visa period in China. They didn't consider my letter, now my application rejected for incomplete documents.
Can I request for reopening my application? what documents can i produce to justify that PCC can't be obtainable for business visa period?