Sometimes you may want to dispute a credit or debit card transaction if:
The transaction was not authorised by you.
The supplier did not deliver the goods or services you paid for.
The goods were delivered to you but were faulty or not as described.
You should contact the supplier first, to seek a refund. If the supplier will not refund your money and you paid using a credit or debit card, your card provider may agree to reverse the transaction. This is called a chargeback.
Dispute rules for each card scheme vary.
The National Consumer Agency has information about chargebacks and how to go about getting one.