Hey,
The same thing happened to me (around the same time as well) and so far, this is what I did:
1. Called my bank and told them I didn't make that transaction. If you are really sure it wasn't a purchase you made, it's entirely possible to ask the bank to help you get that money back. They also have to close your debit/credit card because most likely someone got hold of the info on them (or your paypal account info). In my country, it would take about 2 months for the bank to work it out. They were supposed to hear back from the "online shop" by 4th of January, but so far, I haven't received my money back. Hopefully in a couple of days.
2. Another option is to contact your local police. In my country, it falls under cyber crime and identity theft, so I'm letting them work out who the money actually went to.
I've heard of some other people who had the same thing (unauthorized transactions with "shen zhen shi") happen to them around the same time, so it's most likely a scam
