Scam

Sending someone money is usually done with Apple Cash. If it was regular Apple Pay (debit/credit card) then they could do this - 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

You cannot be refunded if you are scammed. You must report it to the police and report it here - Get Support.

If you are scammed on social media (Facebook/Instagram, etc..) you need to report it to them also.

Contact the bank/credit card company that you used for payment in Apple Pay.