What can a client provide to prove a transaction was legitimate during a dispute?

To establish the legitimacy of a transaction during a dispute, providing evidence of the user's agreement to terms is crucial. This can include documented consent from the user confirming that they understood and accepted the terms of service before making a purchase. This type of evidence demonstrates that the user was aware of the transaction details and agreed to proceed, which can significantly influence the dispute resolution process.

Such agreements typically outline important information regarding the product or service provided, the payment terms, and any refund policies. When a legitimate transaction is questioned, the clarity and transparency around these agreements can serve to reaffirm that the transaction was authorized by the user, thus supporting the merchant's position in the dispute.

The other options, while they may provide some level of proof regarding the transaction, do not carry the same weight in terms of establishing the user’s direct consent to the transaction as the user agreement does. A refund proof demonstrates a subsequent action rather than the original authorization, a screenshot of the sales page may not show individual user consent, and a letter from a card issuer does not specifically relate to the user’s agreement regarding the service or product.