You can easily see the refund done in the same transaction in the "internal trxs" tab:

Any amount not used to buy NFTs is always returned to the user in the same transaction.

You can read more about how refunds work here: https://gemxyz.notion.site/Why-does-it-say-my-transaction-failed-Did-I-get-a-refund-414cc99533eb443bb7e3a026affad0bc