Due to PayPal being a third party gateway, we're limited in the support we can provide. However, I would highly suggest getting in touch with the PayPal Support team regarding these payments as their team will be able to provide you with better information on this situation. You can contact PayPal viathis link.
If at any moment you feel there are fraudulent orders being made on your website frequently, I would like to suggest downloading our free Shopify App,Fraud Filterwhich can provide security when being met with a possible fraudulent order. This can give you a sense of reassurance in the future, knowing that a genuine sale has been made and also will help you navigate sticky situations where you may contemplate whether to fulfill an order or not.
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