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

One day you receive a welcome letter from a phone company you have never heard of, or a text confirming a port you never requested. Your line keeps working, but you are no longer a customer of who you thought. That has a name: slamming, switching your operator or supplier without your consent. It is illegal, it is more common than it looks, and it can be fixed if you act fast.

How do they switch my provider without me noticing?

The mechanism almost always starts with an aggressive sales call. The typical pattern:

1. They call pretending to be your current provider ("we're calling from your operator, we're going to improve your plan") or as an independent comparison site.
2. They ask you to confirm details "to verify the offer": name, ID, address, sometimes your bank details or the code from a letter.
3. With those details and a recording of you saying "yes" to ambiguous questions, they file a signup or a port to another company, which presents that recording as your supposed consent.

Sometimes there is not even a call: it is enough for your details to have circulated (breaches, forms, directories) for an unscrupulous salesperson to file the switch and pocket the commission. That is why slamming usually goes hand in hand with the "yes scam", which we take apart in the "yes" phone scam: a recorded one-syllable "yes" signs no contracts, but they use it as set dressing to pretend you consented.

How do I detect that I have been slammed?

The warning signs:

• Welcome letter or email from a company you never signed up with.
• Porting or signup text you do not recognise. Do not ignore it: it is proof something is moving.
• Your provider stops billing you or you get a final bill with a penalty for "early termination".
• Changes in your customer account or being unable to log in with your credentials.
• The line works but the operator is a different one: on mobile you can see it in the network settings; for electricity and gas, on the next bill.

Golden rule: any message about a provider switch you did not ask for deserves an immediate check. Call your provider (at the official number, one you looked up yourself, never the one in the suspicious message) and ask whether there is any pending process on your line or supply point.

What do I do to reverse it?

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

1. Contact your original provider and explain you never authorised the switch. Ask them to block it if it is still in progress: ports have a window of days in which they can be stopped.
2. Complain to the company that signed you up, in writing and asking for a complaint reference number. Demand the signup be cancelled with no penalty and a refund of everything charged. Key point in your favour: they are the ones who must prove you gave valid consent, not you who must prove you never signed up. Ask them to provide the supposed recording or contract.
3. Do not pay penalties for the fraudulent signup. If they threaten to list you in a debt file for not paying a bill from a contract you never signed, say so expressly in the complaint: an unjustified listing in those files can also be challenged and is sanctioned.
4. If they do not reply or they reject the complaint, escalate: for telecoms, a complaint to your telecoms regulator or ombudsman; for electricity, gas and other services, your consumer protection authority. Keep all documentation and complaint numbers.
5. If they used your ID or details to impersonate you, also file a report with the police. The report strengthens any later complaint.

If the switch came with charges on your bank account, also read how to recover money from a phone scam.

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

• Do not confirm details by phone to whoever calls you. Not your name, your ID, your address or your bank details. If they claim to be your provider, hang up and call the official number yourself.
• Answer with "hello?" instead of "yes", and do not answer strangers' closed questions with one-word replies.
• Check your bills every month: electricity, gas, telecoms and bank account. Slamming shows up on the bill before anywhere else.
• Turn on your operator's alerts: many let you receive porting and line-activity notifications.
• Report the number that called you to sign you up: these campaigns target thousands of people, and the number usually accumulates 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 requested the switch and regretted it, you have a 14-day cooling-off period for distance contracts. Slamming is a switch you never requested: it is not about withdrawing, it is about claiming nullity for lack of consent.

They say they have a recording of me accepting, am I bound? Not automatically. They must prove informed consent: clear identification, information about what was agreed and unequivocal acceptance. Ask for the recording and review it: many fall apart because the information was misleading or the acceptance ambiguous.

Can I go back to my previous provider? Yes, and the company that took you on improperly must bear the cost of restoring the previous situation. Claim that expressly.

How long does it take to resolve? The friendly route with the company takes weeks. The administrative complaint takes months. That is why you should start as soon as possible and keep every piece of paper: time is on your side only if there is a case file.

In short

Slamming lives off two things: your details and your passivity. Deny it the first by confirming nothing by phone, and deny it the second by acting as soon as you see a sign: block the process, complain in writing reminding them the burden of proof is on the company, and escalate to the consumer or telecoms authority if needed. Check your bills every month and report acquisition numbers in the NoCall spam numbers directory. You will find more protocols in our guides.