If Apple Pay or Google Pay says the transaction is not complete, but your bank account displays the charge anyways, you should receive a refund back on your bank account in 1-3 business days.
This happens usually when the zip code on your Apple/Google Pay's shipping address doesn't match the same one on your card.
To successfully purchase the NFT, we recommend checking all the information stored in Apple/Google Pay matches on your credit card, and if it still fails, we recommend retrying using the credit card directly.