Alright , Let me explain to you how does all these bloody warranty works .
Retailers orders from SG/HK reason why they do so, is because they could get cheaper cost to sell to people like YOU.
So , When they get all these so call AP sets from overseas, If anything happen to those faulty device, they've to send it back to either SG/HK for warranty , And when they do so, They use courier service like FEDEX.
When it reach to Sony HK / Sony SG , They will take their sweet time to check the vita this & that , and that might takes up to 2-3weeks minimum for checking , and they'll start repairing and IF only they couldnt repair it they will send a new unit back to the Retailer.
And the reason why they don have the tracking number, BECAUSE EVEN IF WE DISTRIBUTOR send back to them for those non local Sony centre warranty sets it need to wait up to 1-3months.
And , for your info , as i mention above, i DO work in a distributor in Software&Hardware in CONSOLE before, So don't do stupid assuming & asking stupid question how do i know so much about all these how it works.
Thanks