Did it years ago on Silk Road. Made about 10 transactions totally fine, then got rolled. Got an empty package in the mail on a $500 or so transaction. Paid in BTC obv. Guy who did it to me had a good rep and just decided to fuck me for some reason. I heard later on this was a scam some would pull, where every so often they would either not send or just send you an empty, and then say you were just an addict who was lying about never receiving it so you can get free shit.

Believe it or not it was a blessing in disguise because it sent me on the road to get clean and improved my relationship with my daughter.