Apple Pay hack?

Apple Pay is not hackable since it is only a contactless way to pay with your own card. Your card can be compromised but Apple Pay cannot be hacked since there is nothing to hack. if you got a bill that says Apple.com go here - If you see apple.com/bill, itunes.com/bill, or an unfamiliar charge on your statement - Apple Support

if you see charges on your card -

If you see a transaction you do not recognize or have an issue with a transaction open Wallet>tap on the card used>tap on the transaction (photo 1)>tap on the amount (photo 2)>look for a report an issue link. (photo 3)

photo 1 - select the transaction

photo 2 - click the amount

photo 3 - click the link

that has nothing to do with Apple Pay. Cards (new or old) can be compromised in many ways.