Chargeback.

The cardholder disputes a charge with their bank, the money is pulled back out of the merchant account, and the merchant gets a fixed window to answer with evidence or lose the sale and a fee on top. Visa's public rulebook files disputes by condition, among them 10.4 for card-absent fraud, 13.1 for merchandise not received, and 13.3 for not as described or defective (Visa Core Rules and Visa Product and Service Rules). A personalised print defends all three from a weak position. Proof of delivery answers 13.1 and nothing else; a 13.3 argument is about a colour, a placement or a spelling the buyer supplied; and because the item is worth nothing to anyone but the buyer, the standard merchant move of offering to take it back is not an offer. What wins is the file built before the piece printed: the approved proof, the timestamp on that approval, the artwork as uploaded, and a photograph of the finished item.