Enquiry about ordered package at JP post

I ordered some goods from ebay, but have yet to receive the goods so I would like to ask in which way can I check with JP post regarding the package. I only have the tracking number for the goods that leave the country where I ordered the goods. I last checked the status and it had completed the custom clearance and heading to Japan. I have waited for 2 weeks now, but have yet to receive it. Is it possible for me to write an email to JP post to ask if they are holding onto the package? Or is there another way?

If you're certain that your item is going to be handled by JP Post among other companies, use the Track & Trace Service of the following site.
http://www.post.japanpost.jp/index_en.html

If that doesn't work, you need to ask the company that handled the item before that, or for example, this is where you can send your inquiries for JP Post.
http://www.post.japanpost.jp/int/question/tel_en.html

Frankly though, that's the part where parcels tend to get stuck or even lost, according to my experiences.