You check your phone and there's a payment you weren't expecting — €300 on Bizum, a couple of hundred on PayPal or Zelle, or a transfer into your bank account from a name you don't recognize. Minutes or days later, a message arrives: "Sorry, I sent that to the wrong person by mistake — can you send it back?" They're polite. They're in a hurry. It feels like the decent thing to do.
Don't send it back. This is one of the most common money scams running right now, and the way it's built means the person who "helps" is the one who loses.
How the scam actually works
The money that landed in your account isn't the scammer's. It came from a stolen card, a hacked PayPal account, or a compromised bank account belonging to another victim. Sometimes there's no real money at all — just a convincing fake payment notification by email or text.
The scammer's goal is to get you to send your own, clean money to an account they control — usually a different account or phone number than the one the money appeared to come from. Then one of two things happens:
- The real account owner reports the fraud, and the original payment is reversed. The deposit vanishes from your balance — and you've already sent your own money out. You're down twice.
- Even if it isn't reversed, you've just moved stolen funds on a stranger's instructions. Banks and law enforcement call that being a money mule. It can get your account frozen or closed, and in some countries it carries criminal liability — even if you had no idea.
The "overpayment" version
If you're selling something online, the variant is: the buyer "accidentally" pays far too much, sends a screenshot as proof, and asks you to refund the difference — often before the payment has really cleared. Same mechanism, same outcome.
Why "but it was a genuine mistake" doesn't change what you do
Real mistaken payments happen. But a genuine one is reversed by the bank or the payment app through the original transaction — never by you hand-sending money to whoever contacted you. If the sender really did fumble a transfer, their bank can recall it. Your job is simply not to get in the middle. Receiving money never requires you to confirm anything or take any action.
What to do, in order
1. Don't send anything back, and don't spend or move the money
Not the full amount, not "the difference." Leave it sitting where it is. If you've already spent part of it, stop and don't move any more.
2. Don't deal with the sender
Don't reply, don't call any number they give you, don't click their links. Take screenshots of their messages, then stop responding. You don't owe them an explanation.
3. Tell your bank or payment provider — through the official app
Open your banking app or the payment app (PayPal, Bizum, Venmo, Zelle, Cash App) yourself — not from a link — and report that you've received an unsolicited payment you believe is fraudulent. Ask them to reverse it through the original transaction. For a bank transfer, call the fraud number printed on the back of your card. Spain's Banco de España is explicit about this: contact your bank before you move anything.
4. Save the evidence
Screenshot the transaction — amount, date, the sender's name or handle, any transaction ID — and every message. You'll need it for the bank and for a report.
5. Report it
Report the payment inside the app, and report the fraud to the police and your national cybercrime or consumer-protection body — the FTC in the US, Policía Nacional or Guardia Civil in Spain, Action Fraud in the UK.
Not sure how to phrase it to your bank?
Tell Nerva IR which app the money came through and whether you've already sent any back. You'll get a step-by-step containment plan for your exact situation — who to contact, what to say, what to keep.
If you already sent money back
Act now. Call your bank or payment provider on their official channel, say you believe you were defrauded and may have been used to move stolen money, and ask them to try to recall or cancel your payment. Then file a police report. The sooner you move, the better the chance of stopping it. The financial-recovery steps in What to Do After Being Scammed Online apply here too.
What to expect afterward
The original deposit will probably disappear from your balance when the bank reverses it. That's normal — it isn't a new charge, and it isn't your bank taking your money. Watch your account for 30 to 90 days, and be ready for follow-up contact: scammers who get a response often come back, sometimes posing as a "recovery service" that promises to get your money back for a fee. If a message like that arrives, check it first — the guidance in What to Do If You Clicked a Phishing Link covers how to handle follow-up pressure.
The core rule is short enough to remember: money you didn't ask for goes back through the bank, never through you.