PayPal IPN-如果细节有误怎么办？

在IPN文件末尾，它说：

Important: After you have authenticated an IPN message (that is, received a VERIFIED response from PayPal), you must perform these important checks before you can assume that the IPN is both legitimate and has not already been processed:
1.Check that the payment_status is Completed.
2.If the payment_status is Completed, check the txn_id against the previous PayPal transaction that you processed to ensure the IPN message is not a duplicate.
3.Check that the receiver_email is an email address registered in your PayPal account.
4.Check that the price (carried in mc_gross) and the currency (carried in mc_currency) are correct for the item (carried in item_name or item_number).

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如果其中一项检查失败，你该怎么办？我们是否应该以某种方式调用PayPal API来“拒绝”交易？

大多数商店会将未通过这些检查的订单/交易标记为可能的欺诈或类似行为。 订单状态应提高处理订单的员工的意识-仔细查看应显示哪些检查失败，并可以启动进一步的操作

这可能包括从退还交易到联系PayPal以获取可能的欺诈企图。在任何情况下，都应检查订单，而不仅仅将其视为任何其他已完成的订单

示例场景：

您正在使用未加密的网站付款标准HTML表单来接收付款

欺诈买家发现并开始通过编辑提交的表单修改物品的价格

您收到已付款的订单，并且没有根据交易检查您店铺内订单的价值

一名员工没有发现这一点，价值200美元的物品被发送出去，获得0.01美元的付款

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谢谢-所以简短的回答是退款交易或联系贝宝可能的欺诈企图。关于何时以及如何联系PayPal，是否有任何指导原则？e、 g.如果每天超过x次？