I have a parcel bought from AliExpress, with tracking # RG879992409CN.

Tracking information looks OK:
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Parcel No.RG879992409CN tracking result

2017-09-02 22:05:34.0 Electronic Data Received
2017-09-03 14:39:44.0 Dongguan city Post Office eCommerce dept. international parcel process dept. received
2017-09-03 14:46:03.0 Dongguan city Post Office eCommerce dept. international parcel process dept. customs scan
2017-09-03 14:46:33.0 leaving Dongguan city Post Office eCommerce dept. international parcel process dept. ，next station Dongguan center
2017-09-03 15:55:45.0 Guangzhou 邮区center 局international parcel dept. export security scan
2017-09-04 13:30:55.0 Guangzhou Transit Station export customs cleared
2017-09-05 06:58:48.0 arrive Guangzhou Airport
2017-09-05 07:53:08.0 leaving Guangzhou Airport going to next airport/seaport
2017-09-07 09:16:00.0 arrive Philippines Manila Transit Station
2017-09-08 18:10:00.0 arrive customs
2017-09-13 11:01:00.0 Philippines customs 放行
2017-09-15 17:50:00.0 Philippines Post Office attempt delivery
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So as of Sep 15, 2017, the parcel has been released from Customs and on the way to the local post office (here in the Philippines, the post office does not deliver parcels to our address, they only send a notice card [which is quite late] to notify us to pick up the item at the designated post office station).

I went to the local post office maybe a week after Sep 15 to check the parcel, but the post office cannot find the parcel. Since it's just a non-urgent parcel, I didn't mind it and waited for the notice card to arrive.

Oct 11 a notice card arrived with no tracking number (in my experience, the tracking number is written on the notice card if it's a registered parcel; and no tracking number is written if it is an "ordinary/untracked" parcel).

I was wondering what parcel could this be. I went to the post office and claimed the parcel. It is the above parcel that I had been looking for a few weeks ago.

Strangely, the parcel does not indicate China Post "RG879992409CN". It seems to indicate via Singapore post(??).

There's no indication of the tracking number, no wonder our local post office could not find that China Post tracking number.

What shipping was used? (The tracking information above does not indicate the parcel passed thru Singapore. It left Guangzhou, China on Sep 5, and seems to arrive in the Philippines on Sep 7. No indication of Singapore as a transit point?)

Ok, I decided to do some more "detective" work on this. The parcel that I got (supposed to be RG879992409CN <== this tracking number is shown on my AliExpress order page; but is *NOT* really) has the barcode #P000019026615. Based on some research, I found the number belongs to 4PX (AliExpress actually uses 4PX a lot).

when I track that number:
http://xoms.4px.com/home/track/home_index?trackNums=P000019026615

it shows these information:
P000019026615 300089824745 SG ordinary mail+ PHILIPPINES
2017-09-14 18:24 departed from export center
2017-09-12 22:00 HK / Hand over to airline
2017-09-12 21:00 HK / Arrive at facility
2017-09-12 10:56 Shenzhen,China / Depart from facility
2017-09-08 22:40 Shenzhen,China / Shipment operation completed
2017-09-07 20:56 Shenzhen,China / Shipment arrived at facility

So, since 4PX is affiliated with Singapore Post, it uses the label from Singapore Post (parcel didn't go to Singapore, it just makes use of Singapore label) -- in fact, from the above, the shipment type is "SG Ordinary Mail+", and it is actually "ordinary/untracked" rather than registered/tracked.

So the parcel actually took the route: Shenzhen ==> Hong Kong ==> Philippines. But being an 'ordinary' parcel, it has limited tracking information. (The stamped "Sep 22 2017" appears to be from our local Customs department, and so my guess is the parcel really arrived to the Philippines around Sep 22).

Now the mysterious question is: the parcel with tracking number RG879992409CN probably does not belong to me, but its tracking information somewhat matches the time when I ordered the item and its destination is also the Philippines, what a coincidence..