Understanding Discover Chargeback Reason Code NA: No Authorisation

Chargebacks with reason code NA relate to authorisation, and are usually now bundled under reason code AT. However, you may still see chargebacks with the NA label – these specifically address transactions that the issuer claims were completed without a valid authorisation approval.

Key Takeaways

• What it means: The payment was processed with no valid authorisation in place.
• Causes: Skipped authorisation. Forced transactions. Amount increases. Expired approvals.
• How to respond: Supply documents showing the approval code, date, and amount, or proving a refund was given.
• How to prevent: Always obtain approval. Ensure terminals are updated. Follow clear authorisation steps.

What is a Discover Reason Code NA Chargeback?

Note: Reason Code NA has now been merged under Reason Code AT. However, the advice below is still relevant to Reason Code AT chargebacks relating to missing authorisation.

Reason code NA stands for “No Authorisation.” It signals that the merchant completed a charge without obtaining a valid authorisation approval, or that the approval did not cover the final transaction as processed. This falls under the Authorisation category, but it also addresses disputes where consumers deny giving consent. That is why you may see NA on card‑present and card‑not‑present transactions, including phone, mail, and internet orders.

In normal processing, the merchant sends an authorisation request before finalising the sale. The issuer checks the account, confirms the card data, and replies with either an approval or a decline. Only when you receive an approval should you complete the transaction for that exact amount. If a sale is forced through after a decline or captured without any approval on file, it is at risk of a chargeback under NA.

Primary Causes for a Code NA Chargeback

The most common causes for Code NA chargebacks include:

• No authorisation obtained at all. This might happen if a cashier forces a transaction after a decline or completes a sale during a network outage without later obtaining a valid approval. 
• Using an approval that does not match the final amount. For example, adding a tip or extra fee that pushes the total above the approved amount. 
• Using an approval outside the allowed time. Authorisations can age. If you wait too long between approval and completion, the approval may no longer be valid.
• Reusing a prior approval for a new charge. An approval code for an earlier attempt cannot be applied to a different transaction or a different amount.
• Misusing key entry or voice authorisation. Problems arise when the code is not recorded on the receipt, the wrong amount is captured, or the procedure bypasses normal checks like AVS and CVV for card‑not‑present orders.

True fraud and friendly fraud can also sit behind NA. A fraudster might pressure staff to override a decline. A cardholder might agree to a workaround in the moment, then later dispute the charge.

Time Limit for Disputing a Discover Reason Code NA Chargeback

There is a clear time limit to reply. The acquirer or merchant has 30 days to respond to a reason code NA chargeback. The clock starts when the chargeback is issued, not when you first read the notice. If you miss the window, the case will likely stand, even if you later find strong evidence.

Act quickly. Confirm the transaction details in your point‑of‑sale or gateway: date, time, amount, and the full authorisation history. You are looking for a valid approval code that covers the exact amount charged. Check whether the approval was in date when you completed the sale and whether any increase (such as a tip) took the total above the approved sum.

If you have already credited the cardholder, include dated proof of the refund so the issuer can match it to the dispute. If you agreed a new arrangement with the cardholder after the initial issue, gather signed consent or written confirmation, along with the related receipt. Send your package through the route your acquirer specifies and keep a record of the filing time and contents. Good internal routing and a simple checklist help you meet the time limit and avoid last‑minute scrambles.

What NA Means for Consumers & Issuers

For consumers, NA relates to charges that appear without a valid green light from the issuer. If a card was declined or no approval existed, a completed charge should not post. When a consumer disputes such a charge, the issuer checks the records. If the merchant cannot show a matching approval, the consumer’s claim is usually upheld. This protects cardholders from being billed after declines or after unauthorised processing.

For issuers, NA is a rules‑based decision. Their task is to confirm the presence and validity of the authorisation. They examine the authorisation response code, approval number, date and time, and the amount. They may also review network logs to identify a decline or an expired approval. If the evidence shows no valid approval, the issuer supports the chargeback. If a proper approval exists and matches, the issuer can move on to assess any other points in the cardholder’s complaint.

Issuers are not judging the merchant’s intent. They judge the record. Clean authorisation data gives issuers what they need to make a fair call for both parties. Missing or mismatched data often leads to NA cases being decided on the spot.

What NA Means for Merchants

For merchants, NA highlights gaps in authorisation discipline. One skipped step can lead to losing the sale, the goods, and paying fees, plus time spent on admin. Repeated NA disputes can harm your standing with your acquirer and may lead to tighter monitoring. The risk often rises in busy periods, when staff may be tempted to “make it work” after a decline, or when equipment faults lead to workarounds.

Review your flows. Are approval codes always captured and stored with the receipt? Do you ever reuse an approval or add an amount above the approved total? Are voice approvals written on the receipt and stored in your system? In restaurants and service settings, do tips ever take the total beyond the authorised amount? In e‑commerce, do you ever complete an order if AVS/CVV fail and no new approval is obtained? Each of these habits can produce NA chargebacks.

The good news: NA is highly controllable. With clear rules, reliable terminals, and quick access to authorisation logs, your team can avoid the traps. Treat “no valid approval, no sale” as a firm line.

How to Respond to a Code NA Chargeback

First, check if the transaction was properly authorised. If yes, gather and submit:

• The issuer’s authorisation approval (code and response), the date and time, and the amount, all matching the disputed charge.
• A receipt or order record showing a matching amount, date, and merchant details.
• Any relevant terminal or gateway logs, and for card‑present sales, EMV data or imprint if applicable. 
• For online sales, add AVS/CVV results and any 3‑D Secure data.

If you issued a refund, include proof with the date, amount, and reference. If you and the cardholder agreed on a new arrangement after the issue, include the cardholder’s written consent (for example, a signed docket or email) and the corresponding receipt.

If there is no valid approval on record (or the final amount exceeded the approval), your chances are slim. Multiple attempts after an initial decline do not replace the missing approval. In such cases, accept the chargeback and focus on process fixes. Always file your response through your acquirer’s channel, within the 30‑day time limit, and keep copies of everything you submit.

Proactive Prevention: The Ultimate Defence

Prevention starts with one rule: do not complete a transaction without a valid, in‑date authorisation that matches the final amount. Train staff to stop after a decline and ask for another payment method. Keep terminals updated and replace faulty hardware. Record approval codes on receipts, including voice approvals, and store them with the sale. For hospitality, use tip tolerance settings and obtain a fresh approval if a gratuity will push the total higher. In e‑commerce, use AVS/CVV and set retry logic that does not bypass clear declines.

For an added notification layer, try out chargeback alerts to get early warning of inbound chargebacks, allowing you to respond or contest them before they are finalised.