How to Block Your ATM Card or Bank Account After Theft or Fraud

October 15, 2026

2 Views 0

Last updated: 15 October 2026 · By Naijatipsland Editorial Team · Editorial policy

If your phone or ATM card is stolen, or someone has made transactions you did not approve, the first hour matters. The quickest fix is usually to block the card or freeze the account, then protect the SIM, then report to your bank in writing. This guide sets out the steps in order, the bank codes that have been reported to work, and how to escalate to the Central Bank of Nigeria (CBN) if your bank does not help.

Bank codes and contact details change, and several sources here are older than 2026, so we say where each one comes from. Always confirm a code or number on your bank’s own website or the back of your card before relying on it.

The short answer

Block the card or account first. Use your bank app if you can still get in, or call your bank’s customer care from another phone.
Lock or block the SIM next, because a thief can use it to receive your one-time passwords (OTPs). Block lines through your network: MTN 180, Airtel 121 or 198, Glo 121 or 200, 9mobile 300 (from a 9mobile line), per a March 2024 guide.
Report to your bank with your account number, card number and recent transactions, then follow up in writing.
A bank has two weeks to resolve a complaint under CBN consumer protection guidance. After that you can escalate to the CBN Consumer Protection Department.
Some banks offer a temporary freeze you can reverse if you find the card. Others issue a permanent replacement.

Four first steps after card theft or fraud in Nigeria

Step 1: Block your card or account

Use your bank app

If you still have access, this is fastest. Open the cards section and choose Block or Freeze. A September 2026 guide says that on the AccessMore app you can freeze the card there, and a mobility.com.ng guide says MyAccess users go to Cards and Cheques, then Manage Cards, then Block.

Call customer care from another phone

Use the number on the back of your card, your statement or the bank’s website. Tell the agent you want the card deactivated and be ready to confirm your account number, card number and recent activity. Access Bank’s customer care is listed as 0700 CALL ACCESS (0700 2255 22722) or 07003000000, with the email contactcenter@accessbankplc.com. Verify these on the bank’s site, since they come from a third-party guide.

Use a bank code

Some banks have emergency USSD codes. A 2021 Dubawa fact-check, which contacted 12 banks and heard from 8, reported these results. They are old, so treat them as a starting point and confirm with your bank:

GTBank: *737*51*10# to block the card and *737*51*74# to stop unauthorised debits (confirmed by the bank).
Zenith: *966*911# to restrict a compromised account (confirmed). A separate guide says this stops all debits, including the debit card, and that you must visit a branch to resume.
UBA: the code in a viral thread did not work. Dubawa gave *919*10# to block a card and *919*9# to freeze the account.
Wema, Sterling, Fidelity and Keystone also confirmed codes. Wema’s code appeared two ways in the article (*945*911# and *945*9111#), so check it with the bank.
Access Bank: a September 2026 guide gives *901*911# to block the account from any phone, using your registered number and USSD PIN. It notes the exact code should be confirmed with the bank, and says a standard N6.98 session fee applies. Without a USSD PIN, call customer care so an agent can freeze the account after verifying you.

Dubawa did not verify codes for First Bank, FCMB, Union Bank or Heritage because they did not reply. One older guide lists *894# for First Bank, which we could not confirm. For general bank short codes, see our USSD codes guide.

Reported USSD codes to block a card or account at GTBank, Zenith and UBA

Step 2: Lock or block your SIM

Many fraud attempts use the SIM to get OTPs and reset your banking profile. Block the line through your network.

MTN: 180. Airtel: 121 or 198. Glo: 121 or 200 (from another phone). 9mobile: 300 from a 9mobile line, or 08009999999 from another network.
To get your number back, visit an authorised service centre with a valid ID (driver’s licence, passport, voter’s card or NIN slip) and proof of ownership. You may be asked for three frequently called numbers and your last recharge amount.
The March 2024 guide listed a replacement fee of N1,000 on MTN, Airtel and Glo and N1,200 on 9mobile. Confirm current fees with the network.

You can also set a SIM PIN so the SIM is locked after a restart or swap. Dubawa warns to confirm your carrier’s default PIN first, because three wrong entries make the SIM unusable.

Step 3: Report to your bank

Give your account number, card number, the time you noticed the problem and any transactions you did not make.
Ask for a complaint reference number and keep a record of the date and time.
Send a short email as well, listing the disputed transactions and the amounts.
Change your online and mobile banking passwords and PINs once your phone and SIM are secure.
Ask when and where you can collect a replacement card. One guide says it may be mailed to your registered address or collected at a branch, depending on the bank.

If your phone was stolen, get a police report. An Access Bank guide says you may need it, with valid ID, to unblock an account.

Step 4: Escalate if the bank does not help

CBN consumer protection guidance says banks must resolve customer complaints within two weeks and keep you updated. If the deadline passes, you can take the complaint to the CBN Consumer Protection Department. A 2022 Nairametrics guide gives the phone number +234 7002255226, an online complaint form on the CBN website, and a letter addressed to the Director, Consumer Protection Department, which can be delivered to the CBN head office in Abuja or any CBN branch. That guide is from 2022, so confirm the channels on the CBN website before you file.

Include in your complaint:

Your name, address, phone number and email.
The name of your bank and the account details (never your PIN or passwords).
The date and history of the disputed transactions and the amount you are claiming.
Supporting documents, such as statements, screenshots and the police report.
Proof that you complained to the bank first, such as your reference number and emails.

Timeline for bank complaints and CBN escalation

Protect yourself afterwards

Never share your PIN, OTP, token or card details with anyone, including someone who says they are from your bank.
Turn on transaction alerts by SMS and email.
Set a SIM PIN, after confirming your network’s default.
Keep your BVN phone number safe. New CBN rules reported for 1 May 2026 allow only one change of the number linked to your BVN (see our guide to checking your BVN).
Use your bank’s card controls to switch off online, international or contactless use when you do not need it.

Frequently asked questions

How do I block my ATM card quickly?

Use your bank app if you still have access, otherwise call the bank’s customer care from another phone. Some banks also have an emergency USSD code, but confirm it with your bank first.

Can I block my account from another phone?

Some banks allow it. A September 2026 guide says Access Bank’s code *901*911# works from any phone with your registered number and USSD PIN. Other banks’ agents can freeze the account after verifying you.

Will I get my money back?

It depends on the facts and how fast you report. Report immediately, keep records, and escalate to the CBN if the bank does not resolve it in two weeks.

Do I need a police report?

Not always, but a guide on Access Bank says it may be needed to unblock an account after a theft. Get one if your phone was stolen.

How much does a replacement SIM cost?

A March 2024 guide listed N1,000 on MTN, Airtel and Glo and N1,200 on 9mobile. Check with your network.

Bottom line

Block first, secure the SIM second, report to your bank in writing third, and use the CBN only if the bank does not resolve things in two weeks. Save your bank’s customer care number in a second phone or a notebook now, so you are not searching for it in a crisis.