Understanding Discover Chargeback Reason Code AT: Authorisation Non-Compliance

Discover chargeback reason code AT flags sales that skipped, ignored, or mishandled the authorisation step. When approval is missing or does not match the final amount, Discover may pull the funds back. Knowing what it means, why it happens, and how to answer quickly helps merchants protect revenue and customer trust.

Key Takeaways

• What it means: The sale was completed without valid authorisation. Or, the amount or date differed from the original approval.
• Causes: Missed authorisation. Forced transactions after a decline. Expired cards. Submitting a higher total than approved.
• How to respond: Collect the approval code, receipts, and any logs that show the cardholder agreed and that the issuer confirmed the sale.
• How to prevent: Follow the approval process every time and match the approved amount. Renew expired approvals. Try out chargeback alerts.

What is a Discover Reason Code AT Chargeback?

Reason Code AT happens when a cardholder reports a transaction that appeared on their statement, even though they claim the required approval steps were not followed. Merchants must request an electronic, voice, or fallback approval before they capture funds. If they skip that step, push the sale after the card’s expiry date, or alter the amount beyond the tolerance set by Discover, the issuer can recall the money. 

The code falls within the “Authorisation” category, but an AT dispute might also be linked to fraud if the skipped approval meant a stolen card was able to be used. From the network’s view, a sale that lacks a proper go-ahead leaves Consumers, Issuers, and the network exposed. Cardholders get a statement charge they did not expect, the issuer must honour a payment it may not have approved, and the network’s rules lose weight. Because of this, AT disputes carry tight rules and fast deadlines for merchants who wish to fight them.

Primary Causes for a Code AT Chargeback

Several missteps can trigger Code AT. The most common is simple failure to gain any approval at all, often due to terminal error or staff oversight. Ignoring a “Declined” or “Do Not Honour” message and forcing the sale also triggers AT – a shortcut some staff take when put under pressure by a customer. 

Submitting a payment after the card’s expiry date is also risky, as the old date means the issuer cannot verify the current status. Contactless and e-commerce merchants may face AT when DCVV or other security data are missing. This happens because Discover treats absent verification the same as absent approval. A further trigger lies in amount mismatches. If the settled total tops the approved figure by more than the network’s tolerance, the excess can be disputed under AT. 

Time Limit for Disputing a Discover Reason Code AT Chargeback

Time limits exist for both sides of the table. Cardholders normally have 120 days from the processing date to contact their issuer about an AT-related error. Once the issuer files the dispute, the acquiring bank receives a notification. The acquirer, and by extension the merchant, then has 30 days to supply evidence that valid authorisation took place. Missing this 30-day window almost always means an automatic debit from the merchant account. 

After the merchant submits a reply, the issuer reviews the package. They must decide within 30 days whether to accept or reject the representment. Knowing the time limit helps merchants set calendar alerts, gather logs in advance, and react before diaries fill up. Fast action matters more than perfect action; late perfection will not reverse an already-lost dispute.

What AT Means for Consumers & Issuers

For consumers, code AT is reassurance that their bank watches for sales processed outside the rules. When a charge hits an expired card or shows an inflated amount, the issuer can act swiftly to protect the account. The cardholder regains the disputed sum and feels safer about using their card again. 

For issuers, the code is a compliance tool. It promotes cardholder confidence while reducing fraudulent claims. Issuers also avoid funding purchases that lack proper risk checks. Because the network rules make merchants liable for authorisation faults, the issuer’s financial exposure is minimal. Still, banks must investigate each claim, confirm the approval was missing or invalid, and file within the stated deadlines. 

What AT Means for Merchants

For merchants, code AT is a warning that back-office or point-of-sale procedures may need attention. Aside from the direct hit to cash flow, the dispute may carry extra fees from the acquirer and contribute to a higher overall chargeback ratio. Repeated cases can lead to monitoring programmes, higher processing costs, or account closure. 

The dispute also erodes customer trust; shoppers may hesitate to return if they believe their card was mishandled. Operationally, an AT notice often reveals gaps in staff training, software settings, or batch timing. Fixing these gaps not only stops future losses but can speed up checkout and reduce decline rates. Treat every AT case as both a lesson and an opportunity to improve compliance.

How to Respond to a Code AT Chargeback

When the acquirer forwards an AT claim, the merchant should first pull the original approval code. If the system shows a valid code tied to the correct card number, amount, and date, include that screenshot or print-out in the reply. Add the signed or digitally captured receipt, shipping proof, or delivery logs. 

If the approved amount differs from the final settlement, explain any legitimate extras, such as minibar usage in a hotel. Show that it falls inside Discover’s tolerance band. If the first authorisation attempt was declined, then later approved, provide the approved code only. Avoid sending multiple declined codes, as they can weaken the case. File the package within the 30-day limit and keep a copy. 

Proactive Prevention: The Ultimate Defence

Stopping AT disputes before they start is simpler than fighting them later. Adopt terminals and software that request and store approvals automatically. Train staff to read and respect decline messages without exception. Re-authorise when shipping is delayed or the amount grows. Set system checks that block batches if approval is missing. 

For extra protection, try out chargeback alerts for notice of disputed transactions at the earliest stage. This gives your team time to act, whether that's issuing a refund or coming to an agreement with the cardholder before the claim turns into a formal chargeback.

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