If you receive an alert for a transaction you didn't make, lose your phone, or believe someone has gained access to your banking details, don't wait to investigate before securing the account.

Many Nigerian banks provide emergency options that allow customers to block an account, freeze transactions, or block a debit card through USSD, their banking app or a customer-service line.

The exact process depends on your bank.

Here's what to do.

First: Don't Panic — Secure the Account

If you suspect fraud, your first priority should be to stop further unauthorised activity.

Don't spend the next hour arguing with the person who contacted you or trying to determine exactly how the scam happened.

Instead:

1. Secure the account

2. Contact the bank

3. Report the suspicious transaction

4. Change compromised credentials

5. Preserve your evidence

The sooner you notify your bank, the sooner it can investigate and take appropriate action.

How to Freeze Your Account Through USSD

USSD can be particularly useful during an emergency because it generally doesn't require mobile data.

However, use only the USSD code published by your bank's official channels.

Here are emergency options currently published by several major Nigerian banks.

Access Bank

USSD: *901*911#

Access Bank provides a dedicated Block Account service.

Dial:

*901*911#

Then follow the prompts to:

1. Select Block Account
2. Choose Self
3. Enter the phone number linked to your account
4. Select the account—or accounts—you want to block
5. Enter your USSD PIN

Access Bank says the account is blocked once the request is successfully completed. It also says customers can use the service from another phone if their own phone has been lost or compromised.

If you cannot remember your USSD PIN

Access Bank says customers who suspect fraudulent activity and cannot remember their PIN can call 07003000000 from any phone to block the account. Its contact centre is available 24/7.

UBA

USSD: *919*9#

UBA currently lists Freeze Online Transactions through:

*919*9#

UBA's self-service information also provides a Freeze Account option through its digital banking services.

UBA also provides account/card blocking through its USSD service and self-service channels.

Important distinction

UBA's published USSD table specifically labels *919*9# as “Freeze Online Transactions.”

Therefore, don't describe this as necessarily freezing every possible banking channel. The exact service you select on the menu matters.

GTBank

USSD: *737*911#

GTBank currently lists:

*737*911# — Account Block

on its official Bank 737 information.

GTBank also lists Account Blacklist as:

*737*51*74#

on its current 737 features page.

If you suspect fraud, use the emergency account-blocking option and then contact GTBank immediately.

GTBank customer support

GTBank currently lists GTConnect numbers including:

• +234 700 4826 66328
• +234 1 448 0000
• +234 802 900 2900
• +234 803 900 3900

for assistance.

GTBank also warns customers not to disclose confidential banking information to people claiming to represent the bank.

Moniepoint

USSD: *5573*911#

Moniepoint provides an emergency USSD menu for compromised accounts.

Dial:

*5573*911#

Then select:

“Stop Debit Transactions”

and follow the prompts.

Moniepoint says the emergency menu can be used from any phone if your phone has been stolen, and the service is specifically designed to help customers secure their accounts quickly.

Moniepoint says blocking through the emergency menu is free.

If you have already suffered a fraudulent transfer, Moniepoint advises customers to block the account, change their login/authorisation credentials and contact support with the transaction details.

OPay

OPay currently provides an account/card locking option through:

*955*131#

or

*955*132#

for situations such as a lost or stolen phone or card.

OPay also provides 24/7 customer support through its official channels, including:

0700 8888 328

or

020 18888 328

for app and card queries.

What About FirstBank?

FirstBank's current digital banking information includes Account Freeze through its Fibani virtual banking assistant.

FirstBank also provides FirstContact for customer assistance:

0700-FIRSTCONTACT

0700-34778-2668228

01-4485500

0708-062-5000

If you suspect fraud, use the bank's official digital channel or contact FirstContact and specifically request that your account be secured.

What About FCMB?

FCMB currently provides an online Self Service Portal with a specific:

“Block My Account”

option for customers who suspect unauthorised activity.

FCMB also tells customers who suspect unauthorised access to call its contact centre immediately:

01-2798800

or

0700 FCMB BANK

The bank's published contact information should be used rather than numbers found in unsolicited messages.

What If Your Bank Isn't Listed?

Don't guess a USSD code.

Instead:

1. Open your bank's official app

Look for:

Security

Cards

Self Service

Emergency

Block Account

Freeze Account

or Report Fraud.

2. Check the bank's official website

Search specifically for the bank's fraud prevention or account-blocking instructions.

3. Call the number on your debit card

This is often safer than searching for a number through social media.

4. Visit a branch if necessary

If you cannot access your account digitally or by phone, go to your bank.

USSD vs App vs Call Centre: Which Should You Use?

📱 USSD — Best when you need speed

Use USSD when:

• Your banking app isn't working
• You don't have internet
• Your phone is still available
• Your bank offers an emergency blocking code

Advantage: It can work without mobile data.

📲 Banking App — Best when you still have secure access

If you can safely access your banking app, look for the bank's security or self-service options.

You may be able to:

• Block your debit card
• Freeze transactions
• Change your password
• Change your transaction PIN
• Review recent transactions
• Report fraud

But don't stay logged into an account you believe has been actively compromised while trying to investigate suspicious activity for too long.

Secure first. Investigate second.

☎️ Call Centre — Best when you need immediate human assistance

Call your bank if:

• Money has already left your account
• Your phone was stolen
• Your SIM may have been compromised
• You cannot remember your USSD PIN
• You cannot access the app
• You believe your login credentials have been exposed
• You need to report a fraudulent transaction

Tell the agent clearly:

“I suspect unauthorised activity on my account and I need my account secured immediately.”

Then explain what happened.

Don't Confuse “Block Card” With “Freeze Account”

This is one of the most important things to understand.

Blocking your debit card

Usually prevents transactions using that particular card.

Freezing or blocking your account

Can restrict access to the account itself, depending on the bank's specific service.

Freezing online transactions

May only restrict certain digital transactions.

These are not necessarily the same thing.

For example, UBA separately lists Freeze Online Transactions and Block Debit Card among its USSD services.

Access Bank similarly distinguishes between Opt Out of USSD and Block Account. Access Bank says opting out disables USSD banking while blocking the account restricts access to the selected account(s) across channels until the account is unlocked.

So if you believe someone has full access to your banking account, don't assume that simply blocking the debit card has secured everything.

What to Do Immediately After Freezing Your Account

Freezing the account is not the end of the process.

1. Contact your bank

Report the suspected fraud immediately.

2. Report the specific transaction

Give the bank:

• Amount
• Date and time
• Transaction reference
• Recipient/beneficiary details
• How you discovered the transaction

3. Change compromised credentials

If you believe your password, PIN or login details were exposed, ask the bank what should be changed or reset.

4. Block your card if necessary

If your card details may have been compromised, make sure the card itself is blocked/hotlisted.

5. Secure your phone and SIM

If your phone was stolen or you suspect a SIM swap, contact your network provider immediately.

6. Keep evidence

Don't delete:

• SMS alerts
• Emails
• Screenshots
• WhatsApp messages
• Transaction receipts
• Phone numbers
• Account statements

These can help the bank investigate.

What If the Fraudster Is Still Calling You?

Don't negotiate with them.

You may receive a call saying:

“I'm from your bank.”

“We are trying to reverse the transaction.”

“Tell me the OTP you just received.”

“Give me your PIN so we can block the account.”

Stop the conversation.

Access Bank explicitly warns that it will not ask customers for confidential information such as their full card PAN, PIN, OTP, password or BVN.

The safest approach is:

End the call → use your bank's official channel → report the incident yourself.

If Your Phone Was Stolen

Don't wait until you get another phone.

If your bank provides an emergency USSD blocking option that can be used from another phone, use it.

For example:

Access Bank: *901*911#

Moniepoint: *5573*911#

Then contact your network provider to block or replace the SIM.

Also contact your bank and explain that your device and/or SIM has been compromised.

Quick Emergency Guide

These are based on the banks' currently published official information; USSD menus and services can change, so verify the code on your bank's official channel before using it.

The 5-Minute Fraud Response

If you think someone is accessing your account, follow this order:

1. FREEZE/BLOCK

Use your bank's emergency option.

2. CALL

Contact the bank through its official number.

3. REPORT

Give them the suspicious transaction details.

4. SECURE

Change compromised passwords/PINs and block affected cards.

5. DOCUMENT

Keep every transaction reference, message and screenshot.

Don't spend the first few minutes trying to prove whether it's a scam. Secure the account first.

The Bottom Line

If you suspect fraud, speed matters.

Use your bank's emergency USSD, app or customer-service channel to restrict access as quickly as possible.

But remember:

Block the account ≠ report the fraud.

After securing your account, you still need to notify the bank and report any unauthorised transaction.

And never give anyone your:

OTP, PIN, password, card PIN or banking-app login.

If someone calls claiming they can “help you freeze the account” but asks for those details, hang up and contact the bank yourself.