1. For parcel RF287952524CN, this is the full scan:
Parcel No.RF287952524CN tracking result
2016-07-02 08:50:33.0 Electronic Data Received
2016-07-08 13:49:34.0 China Post Group Nanjing city post parcel 局 received
2016-07-08 16:15:00.0 China Post Group Nanjing city post parcel 局 customs scan
2016-07-08 16:20:00.0 leaving China Post Group Nanjing city post parcel 局
2016-07-09 10:53:17.0 Nanjing Transit Station export security scan

2. For parcel RF289080855CN, this is the full tracking:
Parcel No.RF289080855CN tracking result
2016-07-04 08:09:40.0 Electronic Data Received
2016-07-08 13:49:39.0 China Post Group Nanjing city post parcel 局 received
2016-07-08 16:15:00.0 China Post Group Nanjing city post parcel 局 customs scan
2016-07-08 16:20:00.0 leaving China Post Group Nanjing city post parcel 局
2016-07-09 10:53:19.0 Nanjing Transit Station export security scan

3. For parcel RF291989551CN, this is the full tracking:
Parcel No.RF291989551CN tracking result
2016-07-07 08:52:58.0 Electronic Data Received
2016-07-08 13:49:46.0 China Post Group Nanjing city post parcel 局 received
2016-07-08 16:15:00.0 China Post Group Nanjing city post parcel 局 customs scan
2016-07-08 16:20:00.0 leaving China Post Group Nanjing city post parcel 局
2016-07-09 10:53:17.0 Nanjing Transit Station export security scan

4. May I suggest you read this for the above parcels:

What does the status “Export Security Scan” mean? How long it will take?

5. All the above parcels seems to have problems to pass the security check at China Post.

Hope this help.

1. Technically it could be true, but normally no. They always update up to the departure of a parcel. I have never seen that so far here.

2. I don't know what is inside the parcel but they have not pass the security check. Is there anything inside from This:

China Post Forbidden Item List

3. You need to make the decision to wait or to open a dispute to get your money back. You can consult this site for your country:
http://track-chinapost.com/China_Post_Arrival_Time_Stat.php

Hope this help.