SIM swap: my line suddenly stopped working, what do I do?

SIM swap: my line suddenly stopped working, what do I do?

Your phone suddenly shows "No service", "SOS only" or "Emergency calls only". You restart it, you move to another room, and nothing changes, while other people around you on the same network have signal. If this happens out of nowhere, especially after strange calls or messages, take it seriously: it could be a SIM swap, where someone gets a replacement SIM for your number so they receive your calls and, above all, your OTPs and bank codes. The first few minutes matter.

How does a SIM swap work?

1. They collect your details. Name, phone number, date of birth, address, sometimes your NIN, BVN or even a copy of your ID card. These come from data leaks, phishing messages, fake calls "from your bank" or simply your social media.
2. They request a replacement SIM. They pose as you at a network outlet or through a dealer, claiming the SIM was lost or damaged, sometimes using forged documents, and sometimes with help from a corrupt insider.
3. Your SIM is deactivated. When the new SIM is activated, yours stops working. That is the "No service" you see.
4. They take over your accounts. With your number, they receive the OTPs your bank sends, reset passwords for your email and banking apps, and transfer money or take loans in your name. They can also take over your WhatsApp.

What are the warning signs?

• Sudden loss of service on your line while others around you have signal.
• An SMS or call from your network about a SIM replacement or upgrade you did not request.
• Strange calls just before, asking you to confirm details, or calls that ask you to switch off your phone.
• Notifications of password changes or new logins in your email or bank, if you see them on Wi-Fi.
• Your contacts say "you" sent strange messages asking for money.

What do I do right now?

1. Use another phone or Wi-Fi to call your network immediately. Use the official customer care number (find it on the network's official website or ask a relative on the same network). Ask whether a SIM replacement was done on your number and, if so, ask them to block it and restore your line.
2. Call your bank straight after, on the number on your card or in its app (using another phone). Tell them you suspect a SIM swap and ask them to block transfers, cards and internet banking for now. Many Nigerian banks offer a USSD code or an in-app option to freeze your account quickly; ask your bank which one applies and save it in advance.
3. Change your email password from a device you trust, then your banking and other important passwords. Your email is usually the key to everything else.
4. Check your accounts for transactions, new beneficiaries, loans or linked devices you do not recognise.
5. Warn your contacts through another channel that your line or WhatsApp may have been taken over.
6. Go to an official outlet of your network with your ID and NIN to recover your line and get a new SIM.

What if money has already been taken?

• Report it to your bank in writing and keep the reference number. Ask for the transactions to be investigated and the receiving accounts flagged.
• Ask your network for written confirmation of the date, time and place of the SIM replacement. It is key evidence.
• Report it to the police, at a station or through the Nigeria Police Force's National Cybercrime Centre (NPF-NCCC) e-reporting portal, and to the Economic and Financial Crimes Commission (EFCC). Bring the bank statements and the network's confirmation.
• If your bank does not resolve your complaint, escalate to the Central Bank of Nigeria's consumer protection department.
• If your network does not resolve your complaint about the unauthorised SIM replacement, escalate to the Nigerian Communications Commission (NCC) on its toll-free 622 line, following the NCC complaint procedure.

How do I stop it happening again?

• Protect your personal details. Do not share your NIN, BVN, date of birth or ID copies with callers or on social media.
• Never read out OTPs to anyone who calls, even "your bank" or "your network".
• Use an authenticator app instead of SMS codes for your email and other accounts that allow it.
• Set a SIM PIN on your phone so a stolen SIM cannot be used in another phone without it.
• Turn on WhatsApp two-step verification so your number alone is not enough to take your WhatsApp.
• Know your bank's emergency freeze option and save the bank's fraud number in your contacts and on paper.
• Pay attention to sudden "No service". A few minutes of reaction can save your money.

Frequently asked questions

My phone has no service but there is a network outage in my area. Is it a SIM swap? Probably not, if everyone around you on the same network is affected. A SIM swap affects only your line. If in doubt, call your network from another phone.

Can the scammer take my money with my number alone? The number lets them receive OTPs, but they usually also need some of your details or login information. That is why they collect data first. Protecting both makes it much harder.

Will the bank refund me? It depends on the investigation and the circumstances. Reporting quickly, in writing, with evidence from your network, gives you the best chance.

I received a strange call asking me to switch off my phone for a "network upgrade". What was that? A classic SIM swap trick, to give them time before you notice. Never switch off your phone because a caller asks you to.

In short

A sudden, unexplained loss of service can be a SIM swap. Call your network from another phone to block the replacement, then your bank to freeze your accounts, change your email and banking passwords, and report it. And if you received suspicious calls before it happened, report those numbers in the NoCall spam numbers directory.