Quick answer
For an unauthorized card transaction, block or freeze the card immediately, save the debit alert, check recent transactions, report to your bank, request a dispute or chargeback review and keep every complaint reference for escalation.
This guide is written for Nigerians who need a practical next step. It gives the direct answer first, then shows what to verify, what to prepare, what mistakes to avoid and which related Explainer.NG pages can help.
Act immediately
Use your banking app, USSD, bank hotline or branch to block the card. If you suspect your login is compromised, change passwords and secure email or phone access too.
Do not wait to see whether another debit happens. Fraud losses can compound quickly.
- Card block request
- Debit alert
- Merchant name
- Amount
- Date and time
- Location if shown
- Complaint reference
Report and dispute
Tell the bank the transaction was not authorised and ask for the official dispute process. If the card was used online, include whether you received OTP, clicked a link or shared details.
Be factual. Banks investigate based on transaction records, authentication trail and timelines.
Prevent repeat loss
Review subscriptions, saved cards, suspicious links and devices that have banking access. Remove card details from platforms you do not use.
If the bank does not resolve properly, escalate with your complaint trail.
Checklist
- Block card
- Save debit alert
- Report to bank
- Request dispute review
- Change passwords
- Escalate if unresolved
People also ask
Should I block the card first?
Yes, stop further use immediately.
Can the bank reverse it?
It depends on investigation outcome, timing and transaction type.
What if OTP was used?
Still report, but explain exactly what happened.
Should I report to police?
For serious fraud, law-enforcement reporting may be useful.
Can CBN receive complaints?
Yes, after you first complain to the bank and keep evidence.