Understanding American Express Chargeback Reason Code C18: “No Show” or CARDeposit Cancelled

American Express Reason Code C18 applies to lodging transactions when a guest cancels a reservation or is entitled to a refund, yet a charge appears or the credit is missing. It also covers disputed “no-show” fees applied outside the stated policy. It is specific to hotels and similar accommodation providers.

Key Takeaways

• What it means: A lodging booking was cancelled or should have been credited. However, the card was billed, or the refund did not post.
• Causes: Late or unprocessed credits. Unclear policies. Failed cancellation attempts. Invalid “no-show” fees.
• How to respond: Submit policy disclosure, cancellation logs, and proof of credits or policy breaches.
• How to prevent: Display and capture consent to policies. Issue same‑day credits. Provide cancellation numbers. Maintain clear records.

What is an American Express Reason Code C18 Chargeback?

Reason Code C18 relates to the lodging sector: hotels, resorts, serviced apartments, and similar accommodation. It arises when a cardholder claims they cancelled a reservation in line with the rules or were due a refund. However, the charge stands, or the credit did not appear. It also applies to CARDeposit and Assured Reservations bookings.

In practice, the code is used in two broad situations. First, the cardholder cancelled and expected a credit, but the refund was delayed or not processed. Second, the merchant applied a “no-show” fee in a way that did not match the disclosed policy. In both cases, the issuer will review the hotel’s policy, how it was shared, how the guest consented, and what actually happened around the cancellation window.

Primary Causes for a Code C18 Chargeback

Most C18 cases trace back to timing, communication, or policy alignment. A common cause is a delay in processing a credit after a guest cancels. If the refund does not post in the next statement cycle, the cardholder may assume it will not arrive and contact their issuer. Another frequent cause is a valid cancellation that was not logged correctly in the property management system, so the charge proceeds as planned.

Policy clarity plays a major role. If cancellation terms are hidden, ambiguous, or inconsistent on different booking channels, guests may dispute “no-show” fees or late-change penalties. Applying a “no-show” charge that falls outside the stated timeframes, or charging more than the policy allows, also invites a C18 dispute. The same applies if a deposit is captured after the guest has already cancelled, according to the rules.

Operational gaps can contribute. Examples include failed phone or web cancellation attempts, booking system outages, or misaligned settings with online travel agencies. Friendly fraud can also occur, where a guest seeks a refund despite missing the deadline.

Time Limit for Disputing an American Express Reason Code C18 Chargeback

The formal time limit to respond to a C18 chargeback is 20 days for the acquirer or merchant. That clock starts when American Express initiates the dispute. In reality, a portion of the time is taken up by acquirer processing and internal routing. This reduces the time you have to compile and submit a full response. In many cases, your practical window may be a few working days.

Because of this, fast triage is key. As soon as you receive a dispute notice, pull the reservation record, the booking confirmation, the cancellation log or number, and any time-stamped audit trail from your property management system. Gather proof of policy disclosure at booking and acceptance by the cardholder. If a credit was issued, include the credit receipt with date and amount so the issuer can match it to the charge.

Build a concise cover letter that references the American Express case number, sets out the facts in date order, and clearly links each point to the supporting document. Submit your package through the acquirer’s portal within their stated cut-off, and track delivery. Working to a shorter internal deadline helps you avoid timing out and losing the case on process, rather than on its merits.

What C18 Means for Consumers & Issuers

For consumers, Reason Code C18 provides a way to challenge charges tied to cancelled stays or mishandled refunds. It recognises that credits should be processed in a reasonable timeframe and that “no-show” fees must align with what was agreed. That said, it does not override clear, fair policies. If a guest cancels late or misses terms they accepted, the dispute may not stand. The best step for cardholders is to contact the hotel first, keep the cancellation number, and allow time for the credit to post.

For Issuers, C18 cases demand a careful review of timelines, terms, and evidence. Issuers must check if the hotel disclosed a policy, if the cardholder complied with the window, and if the merchant processed a credit. Strong, dated documentation carries weight. Issuers also balance consumer protection with the risk of friendly fraud, where a customer seeks a refund outside of policy. Clear evidence of cancellation attempts or system failures can tip the decision toward the cardholder. Equally, solid proof of late cancellation or credit already issued supports the merchant.

What C18 Means for Merchants

C18 highlights the importance of policy discipline and prompt refunds. Disputes consume staff time, create fees, and can affect your chargeback ratio. Repeated losses also signal to issuers that your documentation is weak, which can make future cases harder to win. It's therefore advisable to make every effort possible in order to avoid these types of disputes from occurring.

Publish cancellation terms at every touchpoint. Capture explicit consent before taking payment or deposit. Provide a cancellation number each time, and keep a log with timestamps. Process credits on the same day, where possible, and advise the guest when they should expect to see the refund. Align your property management system, payment gateway, and settings so cancellations flow smoothly.

How to Respond to a Code C18 Chargeback

Act quickly once the dispute notice arrives. First, read the reason code and match it with the reservation record. If the guest truly cancelled inside the policy and the refund has already been posted, gather the credit receipt, the date stamp, and the amount. Add the booking confirmation, the cancellation records (or absence thereof), and any correspondence where the guest agreed to late arrival terms. 

Should the guest have cancelled too late, supply the timestamp to prove the breach. Keep the narrative short, factual, and free of emotion. Reference American Express rules by section if helpful. Upload evidence in the format requested by the acquirer and submit inside the 20-day limit. Maintain a master log of every document sent. A clear, organised package gives Issuers the confidence to rule in your favour.

Proactive Prevention: The Ultimate Defence

Prevention cuts dispute volume and helps protect revenue. Make policy disclosure visible at the point of booking and in confirmation emails. Capture explicit acceptance before taking payment. Issue same‑day credits when a guest cancels inside the window, and send a confirmation with a cancellation number. 

Keep a single audit trail across your property management system and payment gateway to remove gaps. Train staff to apply fees only as written, and reconcile deposits daily to avoid late captures after cancellations. Chargeback alerts give you time to act before a dispute becomes a formal chargeback. Try out Chargeback.io to get these early warnings.