Transactions are by no means cancelled, and there’s no refund. Nonetheless, the sender additionally doesn’t want to attend for something to occur earlier than trying to make use of their cash in one other method, a minimum of in concept.
When a person broadcasts a transaction, it expresses an try to maneuver the cash concerned. As soon as that transaction confirms, everybody will agree that that occurred. However earlier than affirmation, it’s a matter of perspective. Usually, the sender’s pockets will deal with the cash as gone as quickly because the transaction is created, however so far as the blockchain is anxious, they nonetheless reside within the sender’s pockets.
The protocol doesn’t stop the sender from creating one other transaction that spends the identical cash, which due to this fact essentially conflicts with the primary one (via a precept often called Exchange-By-Price (RBF)). Some wallets permit RBF only for the aim of accelerating the charge of a transaction that’s occurring too gradual, however some additionally permit a person to “abandon” a non-confirming transactions in some circumstances, allowing the funds to be spent in one other means.
Briefly, there may be nothing to refund, as a result of so far as the community is anxious, a non-confirmed transaction merely hasn’t occurred. It’s a matter for the sender’s pockets tips on how to take care of that.