No business is fraud-free. To understand why there is a fraudulent transaction, you have to understand that by law in the United States you are allowed to do reversals up to 180 days from the date of transaction (you can read up on Consumer Financial Protection Bureau).
Some people simply have nefarious intent. They will do the transaction, make the payout happen in the beneficiary country, and then claim that the transaction was a fraud, etc. Sometimes customers don’t understand the charge on their statement and do a reversal without thinking it through. Sometimes, a joint-account is operated and the balance in the account may be $1,800 and the wife has written a check for $1,200 whilst the husband is trying to send $1,500 back home and an NSF (Non-Sufficient Funds) charge occurs. Regardless, the chargeback onus falls on you, as neither the bank wants to take it nor the sponsor, i.e. principal license holder.
The way the US consumer financial protection is set up is prone to abuse, despite multiple features that have been implemented to reduce the chances of fraud. This is the nature of the business. You can argue, this way or that way, at the end of the day, the structure is as such, you are responsible for putting up the reserve for any chargebacks, till such time they are investigated, etc.
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