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ContactCheckup

For sellers

Check the buyer before you ship.

Free tools for people selling on Facebook Marketplace, Craigslist, OfferUp and their own online stores. Spot fake payments, fake buyers and risky orders before you lose the item or your money.

Fake payment email checkerZelle, Venmo, PayPal or Cash App email saying your money is on hold? Check it in seconds.Buyer message checkerPaste a buyer’s Marketplace, Craigslist or OfferUp messages and see the red flags.Order lookupCheck an online order’s name, email, phone and address against public sources before you ship.Report a scam buyerReport the phone number or message so other sellers can recognize it.

The scams sellers run into most

Fake payment emails

An email that looks like Zelle, Venmo, PayPal or Cash App says the money is on hold until you pay or upgrade.

Check a payment email

“Upgrade to a business account”

The most common version of the fake payment email. You’re told to send money so the payment can be released.

Check a payment email

Overpayments

The buyer sends too much and wants the difference back. The original payment is fake or later reversed.

Check buyer messages

Verification code scams

The buyer asks you to read back a code to prove you’re real. It hands them your account or a Google Voice number.

Check buyer messages

Courier and mover pickups

Someone else will collect the item, usually after a payment that never arrives.

Check buyer messages

Stolen-card orders

For online stores: an order paid with a stolen card, shipped to a forwarding address, that later turns into a chargeback.

Check an order

Six rules that stop almost every seller scam

  1. Only trust money you can see in your balance after opening the app or bank yourself.
  2. Never send money, gift cards or codes to a buyer, for any reason.
  3. Never share a verification code, even to “prove you’re real.”
  4. Don’t ship or hand over the item until the payment has fully cleared.
  5. Keep the conversation inside the marketplace app.
  6. For local sales, meet in public and prefer cash.

Run an online store? Use order lookup on orders that look off, like high-value orders, rush shipping or details that don’t match. A free account adds bulk checks and saved reports. ContactCheckup reports are guidance, not a guarantee, and can’t be used for credit, employment, housing or other eligibility decisions.