Slamming: your line switched without your permission, and how to reverse it

Slamming: your line switched without your permission, and how to reverse it

One day you get a text welcoming you to a network you never joined, or confirming a port or a SIM replacement you never asked for. Sometimes the first sign is simply that your SIM shows "No service" while everyone else's phone has signal. You did not request anything, yet your line is no longer where you left it. That has a name: slamming, moving your line or service to another provider without your consent. Its close cousin is the fraudulent SIM swap, in which someone else obtains a replacement SIM for your number. Neither should happen without your agreement, and both can be put right if you act fast.

The stakes are higher than a wrong bill. Your phone number receives your bank alerts and one-time passwords (OTPs), so a line that ends up in someone else's hands can be used to get into your bank account.

How do they switch my line without me noticing?

It almost always starts with a call or message that sounds official. The typical pattern:

1. They call pretending to be your network ("we're calling from customer care, we want to upgrade your line to a better plan") or a sales agent with a special offer.
2. They ask you to confirm details "to verify the offer": full name, NIN, date of birth, address, sometimes your BVN or a code that has just arrived by SMS.
3. With those details, and sometimes a recording of you saying "yes" to vague questions, they request a port to another network or a replacement SIM on your number, and use your details, the code you read out or the recording as proof that you agreed.

Sometimes there is not even a call: it is enough for your details to have circulated (data leaks, forms, directories) for someone to file the request in your name. That is why slamming often goes hand in hand with the "yes" scam: a recorded "yes" signs no contract, but it is used as a prop to make it look as if you agreed.

How do I tell that my line has been switched?

The warning signs:

• A welcome text from a network you never signed up with.
• A porting or SIM-replacement text you do not recognise. Do not ignore it: it is proof that something is moving.
• Your SIM suddenly shows "No service" in a place where it normally works, while other people's phones have signal.
• Your OTPs and bank alerts stop arriving, or you can no longer log in to your network's app or self-service with your usual details.
• Airtime or data disappearing into services you never subscribed to. That is a related problem (unwanted value-added service subscriptions), and the same complaint route applies.

Golden rule: any message about a switch, a port or a new SIM that you did not ask for deserves an immediate check. Call your network (MTN, Airtel, Glo or whichever you use) on its official customer care number, one you looked up yourself and never the one in the suspicious message, or visit one of its service centres, and ask whether there is any port or SIM request on your number. If your line has gone dead, call your bank too and ask them to watch your account until it is sorted.

What do I do to reverse it?

Act in this order, and in writing whenever you can:

1. Contact your original network and explain that you never authorised the switch. Ask them to stop it if it is still in progress and to restore the line to your SIM. The sooner you call, the easier it is to stop.
2. Complain to the network or company that took your line, in writing, and ask for a complaint reference number. Ask for the switch to be cancelled at no cost to you and for anything charged to be refunded. Ask them to show the consent they say you gave (a signed form, a recording, an identity check): if they cannot, point that out in your complaint.
3. Do not pay for a service you never ordered. If someone threatens to report you to a credit bureau over a bill for a contract you never signed, say so clearly in your complaint: you are disputing the debt, not ignoring it.
4. If they do not reply or they reject your complaint, escalate. Under the NCC complaint procedure, you complain to your network first and, if it is not resolved, take it to the Nigerian Communications Commission (NCC) on its toll-free 622 line or through the NCC consumer portal. For problems with other businesses, the Federal Competition and Consumer Protection Commission (FCCPC) takes consumer complaints. Keep every document and reference number.
5. If they used your NIN or other details to impersonate you, also report it to the Nigeria Police Force through the National Cybercrime Centre e-reporting portal (NPF-NCCC). A police report strengthens any later complaint.

If money left your account after the switch, call your bank at once: the sooner they know, the better the chance of stopping or tracing it.

How do I protect myself so it does not happen again?

• Do not confirm details to anyone who calls you. Not your name, NIN, address, BVN or any code that arrives by SMS. If they say they are your network, hang up and call customer care yourself.
• Answer with "Hello?" rather than "Yes", and do not answer strangers' closed questions with one-word replies.
• Watch your signal and your bank alerts. A sudden loss of service, or OTPs that stop arriving, is the earliest warning you will get.
• Ask your network and your bank about SIM-swap alerts and any extra checks they offer before a SIM is replaced or a number is ported.
• Report the number that called you: these campaigns target thousands of people, and the number usually builds up reports in the spam numbers directory that warn the next person.

Frequently asked questions

Is slamming the same as a port I requested and then regretted? No. If you asked for the switch and changed your mind, talk to both networks about moving back. Slamming is a switch you never requested: you are not changing your mind, you are disputing a switch made without your consent.

They say they have a recording of me accepting. Am I bound by it? Not automatically. A recording only helps them if it shows that you were clearly identified, were told what you were agreeing to and agreed without ambiguity. Ask for the recording and listen to it: many fall apart because the offer was misleading or the "yes" was an answer to a different question.

Can I go back to my previous network? You should be able to. Ask your original network to restore your number, and ask the network that took it to cover any cost of putting things back as they were. Put that request in writing.

How long does it take to resolve? Stopping a port or getting a dead line back is easiest on the first day. A disputed complaint with a network can take weeks, and an escalation to the NCC longer. That is why you should start straight away and keep every message and reference number: time is on your side only if there is a paper trail.

In short

Slamming feeds on two things: your details and your silence. Deny it the first by confirming nothing by phone, and the second by acting as soon as you see a sign: get the switch stopped, complain in writing and ask for proof of your consent, and escalate to the NCC if your network does not resolve it. Keep an eye on your signal and your bank alerts, and report the numbers that call you in the NoCall spam numbers directory. You will find more step-by-step guides in our situations section.