Bitcoin does not create a room for refund of bitcoin. But majorly it is rare for there not to be delivery of your fund though. Every merchant has a wallet to check the correspondence of transaction if there's any issue.
I think that bitcoin has been used a lot to buy thing online by criminals and i think that inn the future not only criminals will use it for shopping but then whole world will also do that because bitcoin is a coin that does not have some that looks after it.