Selling online and a buyer's acting strange? Here's what they're doing.
ScamChecker.online·Last verified May 2026·Active and ongoing·5 min read
In a nutshell
Scammers posing as buyers on Marketplace or Craigslist run a few set tricks on sellers.
The big two: asking you to share a "verification code," and sending a fake payment then asking for money back.
The code hijacks a phone number in your name. The fake payment empties your real money as a "refund."
Never share a code, never refund from your own funds. The steps are below.
Our verdict
A "buyer" who needs a verification code, or who overpays and asks for change, is a scammer. No real buyer needs a code to confirm you're real, and no real payment requires you to send money back. The mismatch itself is your signal to stop.
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Does this sound familiar?
You listed something to sell, and a buyer replied fast. The conversation seems normal until it shifts: they want to "verify you're real" with a code, or they've "already paid" and overpaid, and now they need some back. Suddenly it's about codes and refunds, not the item. That shift is the scam starting.
Below are reconstructed examples of the messages sellers receive, recreated to show how they typically look. The opening changes - the move doesn't. (Illustrations, not real screenshots. Names and numbers are fictional.)
‹
K
Kelly M.
Marketplace · active now
Hi, still available? I've been scammed before so I just want to confirm you're a real seller. I'll text a 6-digit Google code to your number - send it back to verify and I'll arrange pickup 👍
9:14 AM ✓✓
The "verify you're real" code is the trap. The code sets up a Google Voice number in your name - not a check on you.
?
Buyer
+1 (555) 555-0156
Text Message · Today 11:02
My assistant sent $450 by mistake instead of $250 for the couch. So sorry! Can you refund the extra $200 back to me? I'll still pick up today.
The "overpayment" is fake or will reverse. Refund the $200 and you've sent real money for a payment that never clears.
P
Payment received?
"I already sent it"
✅ Payment sent! Check the screenshot. Since it's "pending" you need to upgrade to a business account - just send the $50 fee and it releases. Ship once you see it 📦
14:38
The screenshot is fake and the "upgrade fee" is invented. Real payment apps never ask the recipient to pay to receive money.
The opening varies: a verification check, an overpayment, a fake payment screenshot, a "shipping protection" fee. The structure is the same - move you off the item and onto a code, a refund, or a fee.
How it works
These are really two scams that share a setup. Both start with a friendly buyer, then pivot. (The screens below are illustrations of how these messages typically appear.)
1
An eager buyer appears
You get a quick reply to your listing. The "buyer" is keen and agreeable, rarely haggles, and wants to move fast. They often steer you off the platform to text or another app, away from the marketplace's safeguards and reporting.
‹
K
Kelly M.
online
Hi! Is this still available? I can pick up today.
9:10
Yes it is!
9:11 ✓✓
Great. Let's text directly - what's your number?
9:12
Fast, friendly, and pushing to move off-platform. Keep the chat inside the marketplace.
2A
The verification-code trap
They say they've "been scammed before" and want to confirm you're real. They'll send a 6-digit code to your phone and ask you to read it back. That code is a Google Voice (or similar) registration code - reading it back lets them create a phone number in your name to run other scams.
✉ New message · code
Your verification code is
408 716
⚠ This code sets up an account. Anyone you share it with controls that account, not you.
"Send me the code to prove you're real." A code sent to your phone verifies their new account, never your identity.
2B
The fake-payment / overpayment trap
Instead of a code, they "pay" you - and send a fake payment-received email or screenshot, or genuinely overpay with funds that will reverse. Then they ask you to refund the difference, or to pay a "fee" to release the payment. You send real money against a payment that was never real.
Payment Service
no-reply notification
+$450.00
Status: pending - action required
Funds held until recipient sends $50 to upgrade to a business account. Refund any overpayment to complete.
⚠ Fake. Real apps don't hold money pending a fee from you.
Verify money in your real bank or app - never trust an emailed receipt or a screenshot.
3
You're left holding the loss
If you shared the code, a number in your name is now used for fraud, and your linked accounts may be at risk. If you refunded or paid a "fee," that money is gone and the original payment never lands. The item may also be lost if you already shipped.
What it costs you…
↑
Number in your name used for fraud⚠
↑
"Refunded overpayment"−$200
↑
"Release fee"−$50
⚠️
The payment never clears
The screenshot was fake or the transfer reverses. Your refund and fees were real money, sent to a stranger.
No real sale happened. Only your money and your number moved.
Remember
Never share a verification code with a buyer. Ever.
Overpaid and want change? It's a scam. Don't refund.
Confirm payment in your real account, not a screenshot.
Keep deals on-platform. Cash on local pickup is safest.
Red flags to catch it early
None of these alone is proof. Several together means stop.
Asked to share a code sent to your phone
"Read me the code to verify you're real." This sets up a Google Voice or other account in your name. Never share it.
"I'll send a 6-digit code, text it back to confirm"
An overpayment with a request for change
"Sent too much by mistake, send the difference back." The original payment is fake or reverses; your refund is real.
A payment "screenshot" or email as proof
Receipts and notification emails are trivial to fake. Only money showing in your real account counts.
You're asked to pay a fee to "receive" payment
An "upgrade," "release," or "business account" fee. Real payment apps never make the recipient pay to get money.
Pressure to move off the platform
Quickly pushing to text, email, or another app. Off-platform, you lose the marketplace's protections and reporting.
Wants to pay before pickup, won't meet
Insisting on shipping and remote payment for a local item, and avoiding an in-person handover, points to a scam.
Already shared a code or sent money?
If you've just shared a code or refunded a "buyer"
Reclaim, contain, report - in that order
Most of this is fixable if you act quickly, especially the verification-code version.
1
If you shared a Google Voice code, reclaim the numberGoogle has a process to reclaim a Voice number set up with your phone. Go to Google Voice's help, follow the steps to verify and retrieve your number, and remove the scammer's access.
2
Secure your accounts and turn on two-factorIf you shared any other code, treat the linked account as at risk: change the password and enable two-factor authentication, starting with email and banking.
3
If you refunded or paid a fee, contact your bank or payment app nowCall your bank or the app's fraud line. Money sent by Zelle, Venmo, or Cash App is hard to reverse, but reporting fast occasionally helps. Card payments can be disputed.
4
Don't ship the item, and don't send anything moreIf the "payment" hasn't cleared in your real account, the sale isn't real. Any further fee they ask for is the scam continuing.
5
Report the buyer and the listing, then the authoritiesReport the account to the marketplace and file with the authorities below. Be wary of anyone who later offers to recover your loss for a fee - that's a separate recovery scam.
Not sure where to report? Search "[your country] report online marketplace fraud," and report the buyer to the platform you listed on.
How big is this problem?
As peer-to-peer selling moved onto Facebook Marketplace and Craigslist, fraud followed. Two seller-side moves recur across consumer-agency and platform warnings: the verification-code trick and the fake-payment or overpayment refund.12
2 traps
The dominant seller scams: verification-code hijacking and fake-payment / overpayment refunds1
6 digits
A shared verification code is all it takes to set up a Google Voice number in your name2
$100–$2k
Typical price range scammers target - electronics, furniture, tickets - where urgency is highest3
<5%
Estimated share of fraud victims who ever file a report - real totals are far higher than official figures1
The FTC describes online selling scams that use fake payment notices, fake-check overpayments, and Google Voice verification-code tricks; the agency warns sellers never to share a code with someone they don't know and never to refund or wire back an "overpayment."1 The Google Voice version works because the six-digit code texted to your phone is actually a registration code: read it back and the scammer links a Voice number to your number, then uses it to run further scams while concealing their identity.2 Platform guidance describes the same overpayment and advance-payment moves on resale marketplaces.3
The common thread is misdirection. The scam isn't about your item at all - it's about getting you to treat a fake signal (a code, a screenshot, an emailed receipt) as if it were real, then act on it with your own money or your own phone number. The defense is a single habit: trust only what shows up in your real bank or payment app, and never share a code with a buyer. Cash on local pickup sidesteps the whole thing.
Sources
Federal Trade Commission consumer guidance on selling online and avoiding marketplace scams, covering fake payment notices, fake-check overpayments, and verification-code tricks. The two main seller traps, the no-refund / no-code guidance, and the under-5% reporting estimate.
Federal Trade Commission, "Scammers can use your phone number against you" (the Google Voice verification-code scam). How the six-digit code creates a Voice number in your name; corroborated by US state consumer-affairs notices.
Platform anti-scam guidance for resale marketplaces (Meta / Facebook Marketplace), describing overpayment and advance-payment scams and the typical targeted item range. Overpayment mechanics and the price range scammers favour. Figures are illustrative of reported patterns, not a single official total.
Researched and maintained by ScamChecker.online
We document recurring online scam patterns using primary sources - government agencies, law enforcement, and security researchers. The marketplaces and payment apps named here are legitimate services being misused by scammers, not the source of the fraud. We describe the pattern, not specific buyers or platforms. Ads on this page do not influence our reporting. Read about how we research or who we are.
Last verified: May 2026·Reviewed against current FTC guidance