For the current status of packages shipped via postal EMS service, you can trace it at www.ems.com.cn, as this service only with limited tracing capability, it is normal that you may find the status does not change on the website for several days.
Also, as the EMS service is jointly carried out by many countries in a kind of loose corporation, the tracing information we can see on the courier's website is also the all information shared among the postal companies involved, which means it is meaningless to call the courier for additional information, as they can only tell you the same as we can see on their website.
(It is also not all the fault of China Post when a package is delayed, once the package go outside China, then the package is out of control of China Post, the postal services just like a relay in sports, anyone who involved in the race may affect the result, also anyone involved can only affect the progress within their own section.)
Yes, they do provide a status check service if a package not received over 30 days since shipment, but this is done in a very lagging way, they will follow up along the route that the package goes stop by stop, and then send back the result stop by stop again, this may involve many terminals in several several countries, delay from any terminal may delay the whole progress, that is why it may take months for them to advise a checking result, and many of them even end without any result, this is the current situation on the EMS service.
On the other hand, besides the delay of package forwarding within EMS service facility, your local customs may also cause delay to the shipment, this is vary a lot from country to country. Customs delay is totally beyond of our and courier's control. (Customs like Brazil/Russia/Argentinian often cause delay to the delivery)
We will try our best to process your orders as fast as possible, this is what we can do in the whole relay, yet once the package is picked up from our warehouse by the couriers, it is beyond of our control. The shipping chain which connect sellers and buyers in the e-commerce is one of the major problem both sellers and buyers have to face and can not skip, yet it is really beyond of our control, so we both have to face and accept it if any issue arise.
Like many things in the world, EMS has its own advantages and disadvantages, it is less reliable in delivery time and less tracing points than other methods like DHL/Fedex/TNT etc., yet it is cheaper and having less risks of being charged a tax/duties at most destination country customs, this is the advantages side of this service, but for any reason, when you decide to choose EMS over other shipping methods, then you have to accept both the advantages and disadvantages of this service.
Delivery time: the AVERAGE delivery time of EMS service is around 10-20 days, when side average, which also means some time or to some countries, the package may take over 20 days. Besides the factors mentioned above which may affect the total deliver time, the volume/frequency of cargo/passenger exchange between China and your country is another general factor which affect the delivery time, in other words, the more cargo/passenger exchange, the more flights connecting the two countries, the shorter the delivery time, vice versa.
Refer to http://www.himodel.com/en/help/help.php?question=66 for more information on this service.
BTW, it is highly recommended to buy insurance for your orders when ship via postal services.