1. This is the full tracking of your parcel:
China Post Register Air Mail Tracking System
Parcel No.RK506361037CN tracking result
2016-08-08 18:07:42.0 太仓city commerical parcel 广告分公司 received
2016-08-08 18:10:25.0 太仓city commerical parcel 广告分公司 customs scan
2016-08-08 18:21:59.0 leaving 太仓city commerical parcel 广告分公司 ，next station 太仓
2016-08-10 08:24:55.0 Suzhou Transit Station export security scan
2016-08-10 11:41:38.0 Suzhou Transit Station export customs scan (domestic transit )
2016-08-20 14:17:26.0 arrive Suzhou city Post Office parcel process center delivery office
2016-08-20 14:28:37.0 Suzhou city parcel process center received
2016-08-20 14:28:37.0 Suzhou city Post Office parcel process center 已rejected
2016-08-20 14:31:11.0 Suzhou city parcel process center customs scan
2016-08-20 19:45:54.0 leaving Suzhou city parcel process center ，next station Suzhou center
2016-09-02 13:10:13.0 Suzhou Transit Station export security scan
2016-09-02 13:21:59.0 Suzhou Transit Station export customs scan (domestic transit )
2016-09-14 13:09:16.0 arrive Suzhou city Post Office parcel process center delivery office
2016-09-14 13:15:13.0 Suzhou city Post Office parcel process center 已rejected
2016-09-14 13:15:13.0 Suzhou city parcel process center received
2016-09-14 13:17:46.0 Suzhou city parcel process center customs scan
2016-09-14 18:57:30.0 leaving Suzhou city parcel process center ，next station Suzhou center
2016-09-17 10:54:39.0 Suzhou Transit Station export security scan
2016-09-17 11:59:34.0 Suzhou Transit Station export customs scan (domestic transit )

2. May I suggest you contact seller and give him the above tracking and say to him the parcel has not departed China for Mexico. Ask him to call China Post to find out what is going on with your parcel.

3. Your parcel was rejected 2 times:
2016-08-20 14:28:37.0 Suzhou city Post Office parcel process center 已rejected
2016-09-14 13:15:13.0 Suzhou city Post Office parcel process center 已rejected

Hope this help.