My tracking number also changed to a sweden post one a few days ago (delivery address is to UK).. I am equally confused but decided to wait and see
how could it be coming from Sweden? did they explain why when you talked to them? xD
EDIT:
thought i'd ask them myself:
Summer: Your order has been shipped out on 12/4/2013 8:46:54 PM
Summer: Usually it will take 14--30 days to reach you. The delivery time varies from different destinations and different shipping routes.We cannot ignore any unexpected reason causing the delay.You can track via
http://www.17track.net/index_en.shtml and the time depends on your local post .
Summer: It is still in normal transit.
Summer: Pls wait a few more days for it, pls don't worry, it will arrive soon.
Summer: sorry,we do not have united kingdom post now
abhoriel: oh I see, so you are sending it via Sweden post anyway?
Summer: yes
abhoriel: I understand