Chargeback
A forced reversal of a card payment, requested by the cardholder through their bank and open to challenge by the merchant.
The mechanism traces back to 1970s American consumer law, notably the Fair Credit Billing Act of 1974, and has since become part of the card networks' rulebooks. The customer disputes a charge with their issuer and gives a reason, such as fraud or goods that never arrived. The issuer pulls the money back from the acquirer, which recovers it from the merchant and adds a fee on top.
The merchant can fight back with evidence, a process called representment, and in the last resort the card network decides. The industry's big headache is what it calls friendly fraud: customers who received their goods and dispute the charge anyway. Merchants with too high a chargeback ratio land in the networks' monitoring programmes, and if it continues they can lose the right to take cards at all. 3-D Secure shifts liability for fraud disputes to the issuer.