Honestly, there are only two ways to resolve this issue
option 1, call IRCC and complain, maybe they will do something about it
option 2, comply and let you parents physically go to Beijing, I personally don't see why this is an issue with all the planes and rapid train options that we have in China, unless your parents have medical condition prevent them from doing so, of course with some extra ticket money and time
bottomline, I personally consider to be able to re-union with your parents as a privilege. Canadian government is generous enough to offer free med care so your parents can almost truly resident in Canada, unlike our neighbour down South that you either pay sky high insurance for your parents, or fly them back to China if something happens, so request your parents to be physically present at Beijing VAC for PPR is really not that much of a deal in the end
Talk about corruption of VAC? Man I don't know when you moved here to Canada, and by all means I am not anti-communist or anything. You really need to deal with Chinese government officers to realize how they can complicate things up and make you inconvenient.