The reason for the crash is very simple,these china has a gansteril ,corrupted government..It would be almost imposible to claim anything after you lose all your money. If you want some background in these facts check Chinese Huge Scam to 2010-2011 Nasdaq investor through Reverse Merger Chinese Companiies..
Final advise.Get the hell out of Chinese Stocks while you can.Take good advise from a victim.
It's mini de-leveraging as hedge funds in HONGKONG and Japan sell shares to pay back funds, as interest rates are starting to go up. They borrowed tons of money at almost 0 interest rate and now the herd mentality is to get out. Someone will see value when the de-leveraging is over, which may take a few months.
alois: if you have some extra cash, i would try to buy more PTR to average down on your buy at 117. when this stock swings it will swing by a lot (its ups and downs usually at $1+ dollars typical as of late)