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

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

One day a welcome letter arrives from a phone or energy company you've never heard of, or a text confirms that your number is moving to another network when you never asked for anything. Often everything keeps working, but you're no longer with the provider you thought you were. That has a name: slamming, switching your provider or supplier without your consent (with gas and electricity it's known as an erroneous transfer). It's more common than it looks, and it can be put right if you act quickly.

How do they switch my provider without me noticing?

It almost always starts with a pushy sales call. The usual pattern:

1. They call pretending to be your current provider ("we're calling from your network to upgrade your plan") or posing as an independent comparison service.
2. They ask you to confirm details "to check the offer": your name, date of birth and address, sometimes your sort code and account number or a reference from a letter.
3. With those details, and a recording of you saying "yes" to vague questions, they set up a new contract or a switch to another company, which then presents that recording as your supposed consent.

Sometimes there isn't even a call: if your details have leaked (data breaches, online forms, directories), an unscrupulous salesperson can push the switch through and pocket the commission. That's why slamming often goes hand in hand with the "yes" scam, which we break down on the NoCall blog: a recorded "yes" doesn't sign a contract, but they use it as window dressing to make it look as if you agreed.

How can I tell I've been slammed?

The warning signs:

• A welcome letter or email from a company you never signed up with.
• A text about a switch, a number transfer or a new contract that you don't recognise. Don't ignore it: it's proof that something is moving.
• Your provider stops billing you, or you get a final bill with an early termination charge.
• Changes in your online account, or you can no longer log in with your usual details.
• Your service changes without warning: if your mobile suddenly has no signal, your number may have been moved to another SIM, so contact your provider at once; a landline or broadband service can carry on working under a new company; for gas and electricity, it shows up on your next bill.

Golden rule: any message about a switch you didn't ask for deserves an immediate check. Call your provider (on the official number you look up yourself, never the one in the suspicious message) and ask whether anything is in progress on your line or your energy account. With mobiles there's a useful clue: moving a number to another network requires a PAC code (or a STAC code if you leave without keeping your number) requested by the account holder, so a transfer you never asked for means someone has been acting in your name.

What do I do to reverse it?

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

1. Contact your original provider and explain that you never authorised the switch. Ask them to stop it if it's still in progress: the sooner you call, the better the chance of halting it.
2. Complain to the company that took you on, in writing, and ask for a complaint reference. Demand that the contract be cancelled without charge and that everything they've billed you be refunded. Key point in your favour: make them show the evidence of your consent. Ask for the supposed recording or signed contract: a company that switched you properly will have it, and one that slammed you usually can't produce anything convincing.
3. Don't pay charges for a contract you never agreed to. If they threaten to report you to the credit reference agencies (Experian, Equifax, TransUnion) for not paying a bill from a contract you never signed, say so explicitly in your complaint: an unjustified entry on your credit file can also be challenged.
4. If they don't reply or they reject your complaint, escalate. For phone and broadband, where Ofcom sets the switching rules, you can take the case to the ombudsman scheme that company belongs to (the Communications Ombudsman or CISAS) once eight weeks have passed or you've received a deadlock letter. For gas and electricity, complain to the supplier first and then to the Energy Ombudsman; Ofgem is the energy regulator. For advice, contact the Citizens Advice consumer service, which passes reports on to Trading Standards (in Scotland, Advice Direct Scotland; in Northern Ireland, Consumerline). Keep all the paperwork and every reference number.
5. If they used your identity or details to impersonate you, also report it to Report Fraud (formerly Action Fraud) on 0300 123 2040 in England, Wales and Northern Ireland, or to Police Scotland on 101. The crime reference number strengthens any later complaint.

If the switch came with payments taken from your bank account, tell your bank too; you'll find more on getting money back on the NoCall blog.

How do I protect myself so it doesn't happen again?

• Don't confirm details over the phone to whoever calls you. Not your name, date of birth, address or bank details. If they say they're your provider, hang up and call the official number yourself.
• Answer with "hello?" rather than "yes", and don't give one-word answers to closed questions from strangers.
• Check your bills every month: gas, electricity, phone, broadband and your bank statement. Slamming shows up on the bill before anywhere else.
• Turn on your provider's alerts: many let you receive notifications about switches and account changes.
• Register with the Telephone Preference Service (TPS): it's free and makes unsolicited sales calls to your number unlawful, although it won't stop scammers. Unwanted marketing calls can be reported to the Information Commissioner's Office (ICO).
• Report the number that called to sign you up: 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 switch I asked for and then regretted? No. If you agreed to the switch and changed your mind, you normally have a 14-day cancellation right for contracts made at a distance or away from business premises. Slamming is a switch you never asked for: it's not about cancelling, it's about challenging a contract you never consented to.

They say they have a recording of me agreeing. Am I bound by it? Not automatically. They need to show informed consent: who was calling, clear information about what you were agreeing to and an unambiguous acceptance. Ask for the recording and listen to it: many fall apart because the information was misleading or the "yes" was ambiguous.

Can I go back to my previous provider? Yes, and the company that took you on improperly should bear the cost of putting things back as they were. Ask for that explicitly in your complaint.

How long does it take to sort out? Resolving it directly with the company usually takes weeks; an ombudsman case can take months. That's why it pays to start as soon as possible and keep every piece of paper: time is only on your side if there's a paper trail.

In short

Slamming feeds on two things: your details and your inaction. Deny it the first by confirming nothing over the phone, and the second by acting the moment you see a sign: stop the switch, complain in writing and ask for proof of your consent, and escalate to the ombudsman if needed. Check your bills every month and report the numbers that call to sign people up in the NoCall spam numbers directory. You'll find more step-by-step advice in our guides.