I am a cashier at a retail company. 10 times a month we get unsavory individuals who comes to purchase multiple Visa gift cards. At the POS the'll attempt to complete the transaction with their prepaid credit card. The first attempt always gets denied. They'll continue swiping multiple times until it eventually gets approved. Our company states that they have no control over such a transaction and also we cannot simply refuse to serve these individuals in fear of repercussion from the law. As a hard-working individual, what can I do or say within the means of the law to prevent this from happening?