Overpayment scam

In a check overpayment scam, the scammer will pay the victim for goods or services (often in response to an online or classified advertisement, though there are a number of other premises for check overpayment scams) with a fraudulent check of an amount in excess of the intended amount. In some cases, the scammer will claim that the difference between the intended amount and the amount on the check is due to customs or other import fees, or shipping fees.[1] The fake check can present either as a personal or cashier's check. The scammer then requests that the victim pay them the excess between the intended amount and the amount on the check.[2] After the victim does so, they discover that the scammer's check was fraudulent, losing their money. In addition, if the check was sent in response to an online or classified advertisement and the victim has already sent or delivered the item being sold to the scammer, the victim loses their item as well.

The check variant of the overpayment scams, as well as other confidence tricks where scammers send the victim an illegitimate check, work in part because of the delay—sometimes days or weeks—between a customer depositing a check at a bank and the check clearing and being verified as legitimate.[3]

In an online refund scam, a scammer usually finds potential victims by cold calling phone numbers until there is a responsive victim. The scammer pretends to represent either a well-known large company or a smaller company offering a service of some kind. The scammer tells the victim that the company owes the victim a refund either for a product that the victim supposedly ordered or a service that the company can no longer provide. The scammer will request to access the victim's computer using remote desktop software, and then ask the victim to log in to their online banking website. The scammer blanks the victim's screen using the remote access software, and uses the web development tools of the victim's browser to temporarily edit the online banking webpage to show a transfer into the victim's account. While no transfer has actually taken place, when the scammer restores the victim's ability to see the screen, the edited version of the webpage may convince them that the scammer did indeed transfer money into their account.[4]

After the victim believes that a transfer has gone through, they then discover that the amount supposedly transferred into their account is larger than expected. Using the good faith of the victim against themselves, the scammer often claims that their job is at stake if the victim doesn't return the difference between the intended amount and the supposedly paid out amount. The return is done by wire transfer, money order, or sometimes by store gift card, which the scammer then redeems, making it near impossible for the victim to retrieve their money after being scammed in this way. Some amount of time later, the victim then finds out (possibly by reloading their online banking website, as reloading the page removes the scammer's changes) that the scammer never transferred any money into their account at all, and that any money sent to the scammer has been lost.[4]

Online refund scams can also be considered a form of technical support scam, as they largely follow the same format of connecting to the user's computer with remote access software. In addition, some online refund scams have been specifically targeted at users who had previously fallen victim to technical support scams, claiming that the company which originally conned the victim had gone out of business and could no longer provide the "security services" the victim paid for in the original scam.[5]