1. This is the full tracking of your parcel:

China Post Register Air Mail Tracking System
Parcel No.RH287457525CN tracking result
2016-08-26 19:17:19.0 Guangzhou Int'l Parcel Center received
2016-08-26 19:17:28.0 Guangzhou Int'l Parcel Center customs scan
2016-08-26 22:13:21.0 leaving Guangzhou Int'l Parcel Center ，next station 广商大宗
2016-08-28 02:02:23.0 Shanghai Transit Station export security scan
2016-08-28 03:58:40.0 Shanghai Transit Station export customs cleared
2016-08-29 23:56:00.0 arrive Shanghai Int'l Airport
2016-08-30 00:03:14.0 leaving Shanghai Int'l Airport going to next airport/seaport
2016-09-01 17:38:00.0 Shanghai departure
2016-10-06 09:09:36.0 Beijing Transit Station import customs scan
2016-10-06 12:20:50.0 Beijing Transit Station import customs cleared (domestic transit )
2016-10-09 07:35:28.0 Shanghai Transit Station import customs scan
2016-10-09 09:42:29.0 Shanghai Transit Station import customs cleared (domestic transit )
2016-10-10 09:53:57.0 arrive 梅陇dept. delivery office
2016-10-10 11:16:25.0 梅陇dept. attempt delivery
2016-10-10 11:17:25.0 梅陇dept. delivered

2. For what ever reason the parcel was not deliver to USA or was sent back from USA. You should check with USPS first, then contact seller because it was sent back to him and deliver.

3. Another tracking here the same thing:
Number: RH287457525CN
Package Status: Delivered ( 45 Days )
Destination Country: United States

Crigin Country: China
2016-10-10 11:17 Mei long branch, has been voted
2016-10-10 11:16 Mei long branch, is posted
2016-10-10 09:53 Mei long branch, arrived at post
2016-10-09 09:42 Shanghai Exchange Bureau, import each other (internal transit)
2016-10-09 07:35 Shanghai Exchange Bureau, import opening
2016-10-06 12:20 Beijing Exchange Bureau, import each other (internal transit)
2016-10-06 09:09 Exchange Bureau in Beijing, has imported opening
2016-09-01 17:38 Shanghai Qi Yun
2016-08-30 00:03 Shanghai Pudong, left hand navigation
2016-08-29 23:56 Shanghai Pudong, reach
2016-08-28 03:58 Shanghai Exchange Bureau, have been exported directly
2016-08-28 02:02 Shanghai Exchange Bureau, have been exported to open
2016-08-26 22:13 Canton international parcel, left, next stop "wide-large"
2016-08-26 19:17 Canton international small packet, sealing
2016-08-26 19:17 Canton international parcel has been accepted
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Hope this help.