How to Report an Unauthorised Bank Transaction in Nigeria

Discovering an unauthorised bank transaction can be frightening, especially when money has left your account without your approval. Act quickly, but do not panic. Your first priorities are to stop further withdrawals, notify your bank through an official channel and preserve evidence.

An unauthorised transaction may be a card payment, ATM withdrawal, transfer, direct debit, mobile-app transaction or another debit that you did not approve. The reporting process is broadly similar, although your bank may ask different questions depending on the transaction type.

What to do immediately

1. Contact your bank through an official channel

Use the phone number on your bank card, the bank’s official website, its mobile application or a branch. Do not use a telephone number sent to you in an unexpected text message or social-media reply.

Tell the bank clearly that you are reporting an unauthorised transaction. Ask the bank to:

• Place a restriction on the affected card, account or digital banking channel where appropriate.
• Stop or review any pending transaction connected with the incident.
• Open a formal dispute or fraud report.
• Provide a complaint or reference number.
• Explain the next steps and the documents required.

If you believe your card details have been exposed, ask whether the card should be blocked and replaced. If your banking application or email account may have been compromised, change the relevant passwords using a trusted device and ask the bank to review access to your digital banking profile.

2. Do not share sensitive security details

Your bank may need to verify your identity, but legitimate staff should not require you to disclose your full PIN, internet-banking password, one-time password or card security code to investigate a complaint. Never share these details with someone who calls unexpectedly and claims to be helping you recover funds.

Do not click links in suspicious messages. If you need to log in, open the bank’s official app or type the bank’s known web address yourself. Fraudsters sometimes pretend to be bank employees and use the urgency of an unauthorised debit to obtain another transfer.

Collect the details your bank will need

Prepare enough information to help the bank identify the transaction. You do not need to publish these details online or send them to anyone other than the bank through a secure, official process.

• Your name and the affected account or card details, following the bank’s secure identification process.
• The date and time of the transaction, if shown.
• The amount and transaction description.
• The transaction reference or session ID, if available.
• The channel involved, such as ATM, point-of-sale terminal, bank app, USSD, card payment or online transfer.
• When you first noticed the transaction.
• Whether your phone, SIM card, card, account credentials or email account was lost, stolen or accessed by someone else.

Take screenshots of the debit alert or account statement, keeping the date and transaction reference visible. Save relevant SMS messages, emails, call logs, receipts and chat records. Do not edit screenshots in a way that removes important information.

Report the transaction in writing

A telephone call can be useful for immediate action, but submit a written complaint as well if the bank permits this through its official email, secure app or branch. Written records make it easier to track what you reported and when.

Your complaint should include:

• A clear subject such as “Unauthorised transaction dispute”.
• The transaction date, amount and reference.
• A statement that you did not initiate or authorise the transaction.
• The action you have already taken, such as blocking a card or changing a password.
• A request for investigation and written confirmation of the outcome.
• Your complaint reference number, if one has already been issued.

Keep a copy of the complaint and note the names or identification details of staff who handle it where those details are provided. Avoid sending your PIN, password, OTP or complete card security information in an email or social-media message.

Different transactions may require different action

Unauthorised card payment

Ask the bank to block the card and dispute the payment. If the payment is still pending, ask whether it can be stopped or reviewed. If the card is lost or stolen, report that fact immediately and follow the bank’s replacement procedure.

Unauthorised ATM withdrawal

Report the withdrawal as soon as possible. Give the bank the ATM location, time and amount if shown in your records. If you still have the card, state that clearly. The bank may review ATM records and other information as part of its investigation.

Unauthorised transfer or mobile-banking transaction

Ask the bank to place an urgent trace or recall request where applicable. Recovery is not guaranteed, particularly if the money has already moved through another account, but delaying the report can make investigation more difficult.

Secure the account used to approve the transaction. This may include changing your banking password, disabling a compromised app session, contacting your mobile network provider if your SIM may be involved and checking whether your email account has been accessed.

Transaction caused by suspected impersonation or scam

Tell the bank exactly what happened, even if you shared information or approved something after being deceived. Do not hide relevant facts. Explain whether someone impersonated a bank employee, online seller, relative, employer or government organisation.

Keep the scammer’s phone number, account details, website address, usernames, messages and payment receipts. Do not continue negotiating with the person or send more money to “unlock” a refund.

What happens after you complain?

The bank may investigate the transaction, review access records and contact other institutions involved in a transfer or card payment. It may ask you to complete a dispute form, provide identification or make a statement. Respond through the bank’s verified channels and keep records of every additional document you submit.

Ask when you should expect an update, but understand that the investigation period can depend on the transaction type and the institutions involved. A provisional credit or refund may not be automatic. Do not assume that a debit alert has been reversed until you confirm it in your account through an official channel.

If the bank does not resolve the complaint

First, follow up with the bank using your complaint reference number and ask for a written response. If the matter remains unresolved after you have used the bank’s complaint process, you may escalate it through the appropriate consumer-protection complaint channel of the Central Bank of Nigeria. Use the CBN’s official website to confirm the current escalation procedure and required documents before submitting a complaint.

For suspected criminal fraud, identity theft or threats, consider reporting the matter to the appropriate law-enforcement authority. A bank complaint and a law-enforcement report serve different purposes, so keep copies of both where relevant.

Common mistakes to avoid

• Waiting several days before notifying the bank.
• Deleting messages, receipts or transaction alerts.
• Sharing an OTP, PIN or password with a supposed support agent.
• Posting account numbers, phone numbers or transaction screenshots publicly.
• Sending money to someone who promises to recover the original funds.
• Assuming that a familiar merchant name proves you made the payment.
• Making a false claim about a transaction you authorised but later regretted.

A simple response plan

1. Confirm the transaction in your official banking app or statement.
2. Contact the bank immediately through a verified channel.
3. Block or restrict the affected card, account or digital access where necessary.
4. Change compromised passwords and secure your phone, SIM and email account.
5. Submit a written dispute and request a reference number.
6. Preserve alerts, screenshots, receipts and communication records.
7. Follow up and escalate through the appropriate official channel if the complaint is not resolved.

The most important rule is simple: report quickly and share only what is necessary through official channels. You can give your bank the transaction details it needs without handing over the security credentials that protect your account.