收到信内容如下“Your offer of XXX has been suppressed because the negative customer experience (NCX) rate on recent orders is considerably higher than for similar products. The NCX rate takes into account returns, refunds, customer service requests, and negative product reviews. Visit the Seller Central Help Center to learn more about NCX notifications or about resolving CX Health issues.”
Because your offer has been suppressed due to a high NCX rate multiple times, we will proceed in one of two ways: 
• If the customer complaints indicate product defects that can be visually confirmed in our fulfillment centers (for example, mislabeled or damaged inventory), we will initiate an Amazon conducted investigation into your inventory currently stored in the fulfillment centers to ensure the product meets the product description and is free of damage.
• If the customer complaints indicate product defects or other issues that can't be visually confirmed in our fulfillment centers (for example, a product malfunctioned or was of poor quality in performance), you will need to submit a Plan of Action that addresses the customer issue(s).

但我们产品NCX是excellent的，没有接到大量差评或退货退款，也没有客人找我们投诉什么。这"Blocked"来得突然，一下子就红标不给重上，百思不得其解，后台amazon自动开了一个case给我，标题是"产品investigation",没有其它内容。然后就是上面那封邮件。我的问题是：
1。这种investigation的block有人遇过吗？按amazon给的邮件是找不到原因的。只有一个case在等他们回复。
2。如果跟卖不断退货会block我的listing吗?订单是跟卖的应该不关我事吧？
3。会不会是对手恶意买大量我的产品再全退款造成的呢？买家号这种操作不会死帐号吗？如是这情况amazon竟然会怪卖家？
3。这情况会不会是竞争对手恶意投诉呢？这样不是每个买家号都可以把人搞死？amazon没机制防止吗？