I was hit by this two months ago. My bank recognized it, did not process it and put a hold on my card for any merchant transactions until they could contact me.
I of course, did not approve the transaction. Had my card cancelled and ordered a new one.
I cannot be certain but this happened about 6 hours after I made a purchase online at Amazon.com through a vendor one their market place. Since then, I changed my account information, removed my card from storage on their servers and purchase an Amazon gift card when purchasing through their site.
I have read the horror stories people have had with these transactions. Got to keep your cards safe.
In Feb we had found out our debit card was compromised in just this way. Small amounts a few each day in online transactions which we do very little of. Thank God my husband confronted me early asking for receipts ( He is the ledger Nazi). The bank cleared everything up in about a week. We no longer have debit cards. We buy prepaid gift cards for online shopping. A bit of a pain but worth it