Lost applicatoin package?

I mailed my sister's application packages (DS-230, all required certificates ) on Oct 14 with priority mail and delivery confirmation.  Since I haven't gotten any update from NVC, I sent emmail to ask them, the reply was that it's not received. I know it takes a month to get packages opened by officer, but it's almost 2 months.  What should I do if package is lost ?

所有跟帖： 

• did you track your package? -shuiliu- ♀ (0 bytes) () 12/10/2010 postreply 10:24:16

• 回複：Check the tracking number to see when the package was delieve -youxiwang- ♀ (137 bytes) () 12/10/2010 postreply 11:09:48

• Thanks for reply, I had delivery confirmation, I will call USPS -AMK666- ♀ (0 bytes) () 12/10/2010 postreply 17:07:53