fraudulent charge on debit card held in my Apple Wallet

My debit card was fraudulently charged an amount at the exact same time I used it to make a purchase from my Wallet on my Apple Watch this evening. My wife's debit card was also fraudulently charged this evening for the exact same amount at the same noted place as was mine. Both debit cards are from the same financial institution. They have now been closed. Any ideas on how this may have occurred and/or thoughts on what other action should be taken? Thank you.