Customer says they didn't make the purchase

Mastercard 4837 is the Mastercard counterpart of Visa 10.4 (customer says they didn't make the purchase). The customer says they did not make the purchase, and the evidence looks similar: the billing-address check (AVS), CVC2 (the security code on the card), 3D Secure (the bank's identity check at checkout), a record of the buyer's device, the buyer's internet location, prior history, and delivery.

How it arrives

The customer has up to 120 days from the sale to file. Most file within 30 to 60 days, when their statement arrives. Your payment company (Stripe, Shopify Payments and the like) sends the notice, which carries the dispute reason (the code on your notice), with the claim summarized in a sentence. Respond before the date on that notice. Your payment company sets it, and it comes before the card network's own limit.

For a store selling digital goods, a 4837 often arrives months after the buyer used the product. For a store shipping physical goods, it often arrives after the parcel reaches the customer's billing address.

What the issuer is looking for

The customer's bank asks whether the real customer was responsible for the sale. No single piece of evidence decides it.

• The billing-address check and the security code. They show the buyer knew the billing address and the printed code. In 2026 they are not enough alone.
• 3D Secure. If the customer's bank verified them at checkout, responsibility shifts away from you for that sale. Mention it if you have it.
• A record of the buyer's device, the buyer's internet location, and session history. These matter most when the customer says they were not at their computer.
• Prior orders from the same card to the same shipping address. Positive feedback or no earlier disputes strengthens the picture.
• Delivery confirmation to the verified billing address. This closes the case for physical goods.

Mastercard's rules on using earlier orders as proof differ from Visa's, and arguing from the wrong ones loses on a technicality.

Common scenarios and the evidence for each

• Buyer used the card, received the goods, and now claims fraud. Login records, an internet location matching earlier legitimate sessions, and any message from the buyer after delivery.
• Family member or partner placed the order. Under Mastercard rules the customer is generally responsible for household members with access to the card. Show the order shipped to their address and was kept.
• True account takeover. These are usually unwinnable. Fighting genuine fraud raises your dispute ratio and recovers no revenue.

When the buyer disputes the goods

If the buyer says they received the goods but they were not what they ordered, the dispute belongs under Mastercard 4853 (the customer disputes the order). Proof of delivery will not help on a 4837.

How we help

4837 is the highest-volume Mastercard fraud reason we draft responses for. Each response is built from your billing-address and security-code results, your 3D Secure result, session evidence, the buyer's history with you, and the relevant Mastercard rule. If you have received one, your first response is free. Try free.