Where do I find Refunds made to Apple Pay

I made a purchase from an online vendor, however, it had to be returned. I used Apple Pay to make the purchase, it did not give me the option of even showing what card was being used, but it went through just fine. When the vendor received the return they said they would refund in full. However, nothing showed up on my various credit cards and it has been some time. I reconnected the vendor and they said they would send me an invoice that showed that the transfer of the refund went through to Apple Pay.

It will be several days before I get the invoice.

In the meantime, how to I locate where this refund supposedly went. I have reviewed all my associated credit cards and nothing shows up anywhere.

Thanks!