Apple Pay

Here is a visual representation of what Rysz said -

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

Select the transaction, scroll down, then tap on the Report an Issue button.

Or start with the Contact Support grey link at top-right of this page.

go here - Apple Pay Customers

If you go to Wallet and hit the plus sign you may be able to re-add the card.