Or, they made use of your own modem, and picked up your password and card digits direct from your computer? Have you got a good password for your modem? Maybe consider changing it? They say NEVER to use public WIFI to buy anything...I wouldn't. If I was to go to the library to use a computer, I'd be sure to close the browser before I left, even if I was just looking at Stunthangar.com
I have also heard about people accidentally "butt buying" stuff when they have their card numbers saved at an online store like Amazon (or Brodak's, I suppose). That's one of the joys of having a smart phone and using it to buy stuff! The cure is to NOT allow the vendor to keep your card numbers.
Sorta related...the first time I have gotten a credit card hacked, was this last July, right after the first time I EVER paid by card at a fast food place. A day later, I got the call from BECU Visa security, asking if I had just been buying stuff in Texas and Colorado. Took awhile, but I got a new card...kept me from being able to go to the WCSC contest...it's so much easier to use a card across the border that I'm never going to mess with getting Canadian cash ever again. While I was at it, I got another card from US Bank and choose to use it because I earn 1.5% cash back on it. I've been meaning to take my BECU Visa card back to that same fast food restaurant and see if it happens again.
Before I retired, one of my co-workers drove out for lunch and went through the drive-through lane at a local chain fast food place...and paid with his credit (not debit) card. He was sharp enough to keep an eye on it, and saw the girl run the card and then writing the numbers and 3 digit security number on a notebook. He sat there blocking the lane and dialed 911 on his cell phone. The cops came and arrested the girl. Probably slapped her wrists.
Our Renton police don't respond to misdemeanor incidents...they prefer to remain on standby waiting for felonies, apparently? Don't want to do the paperwork, when the courts just turn the miscreants loose? My theory is that if they'd catch and persecute (!) people for misdemeanors, those folks may be less inclined to step up to felony crimes, but that's just my whacked-out theory.