关于美区 PayPal 各种失败、各种 Sorry 的解决以及客服解释，另外能绑 AppStore 不能绑阿里云也是存在的

上次注册 PayPal，注册好后能付款，能绑定 appstore，不能绑定阿里云。联系客服解决问题，用了一个月被封。
本次注册好后，不能付款，不能绑定 appstore，不能绑定阿里云。再次联系客服，并询问了一些细节。

第一次表示无法付款：

I see the transcation is stopped by a security check. I will review this further to see if there is anything I can do to help. 风控系统起作用了，导致不能付款。经过客服操作，可以成功付款和绑定 appstore 了。

客服再次解释：

Our security program considers a variety of factors at each transaction. After reviewing your account,I can see that for this occasion, this transaction Will not go through. This is only impacting this specific transaction and it is possible you won't encounter this problem With future transactions. I wish there were more I could do.
说明确实存在能绑 appstore 不能绑阿里云的问题。

请求客服解禁阿里云：

I wish I could assist you with getting this payment through, but, our security system is putting a stop to it.
I would suggest that you try making this payment outside PayPal.

已经被系统拦截了，并且客服也无能为力了。

因此，猜测 paypal 风控有几个级别，比如能正常使用，限制阿里云等部分商家，限制全部商家。再高……就该 Your account is limited 了吧？？