1. Here is a tracking of your parcel:

International Mail# RJ911809898CN Tracking Result
Summary
Tracking number Origin Destination Status
RJ911809898CN CHINA CZECH REPUBLIC Posted
History Detail
Local date/time Activity Location Remarks
30-Nov-2016 00:17 Received by Post Office 32206600

2. Here another tracking:
Number: RJ911809898CN
Package Status: In Transit
Destination Country: Czech Republic
2016-11-30 00:00 The consignment was posted.
Origin Country: China
2016-11-30 09:04 Yiwu Exchange Bureau, have been exported to open
2016-11-30 02:30 Directorate of international e-commerce, Yiwu city, away, the next station "Yiwu"
2016-11-30 01:38 Yiwu international electronic commerce branch
2016-11-30 00:17 Directorate of international e-commerce, Yiwu has been accepted
======================================
Powered by http://www.track-chinapost.com

3. And the last tracking:

China Post Register Air Mail Tracking System
Parcel No.RJ911809898CN tracking result
2016-11-30 00:17:44.0 Yiwu city international eCommerce dept. received
2016-11-30 01:38:51.0 Yiwu city international eCommerce dept. customs scan
2016-11-30 02:30:46.0 leaving Yiwu city international eCommerce dept. ，next station Yiwu
2016-11-30 09:04:27.0 Yiwu Transit Station export security scan

4. To me according to the above tracking your parcel did not pass the Export Security Scan from China Post. More info here:

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

5. Just open a dispute with the seller for non reception of Parcel. It's not up to you to call China Post but the sender has to do that for you. Nor very cooperative your seller.

6. In your dispute you can put the above 3 tracking I gave you.

Thanks.